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  • Articles  (1,196)
  • Models, Molecular  (673)
  • Mice, Inbred C57BL  (531)
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  • 1
    Publication Date: 2010-10-15
    Description: The pre-T-cell antigen receptor (pre-TCR), expressed by immature thymocytes, has a pivotal role in early T-cell development, including TCR beta-selection, survival and proliferation of CD4(-)CD8(-) double-negative thymocytes, and subsequent alphabeta T-cell lineage differentiation. Whereas alphabetaTCR ligation by the peptide-loaded major histocompatibility complex initiates T-cell signalling, pre-TCR-induced signalling occurs by means of a ligand-independent dimerization event. The pre-TCR comprises an invariant alpha-chain (pre-Talpha) that pairs with any TCR beta-chain (TCRbeta) following successful TCR beta-gene rearrangement. Here we provide the basis of pre-Talpha-TCRbeta assembly and pre-TCR dimerization. The pre-Talpha chain comprised a single immunoglobulin-like domain that is structurally distinct from the constant (C) domain of the TCR alpha-chain; nevertheless, the mode of association between pre-Talpha and TCRbeta mirrored that mediated by the Calpha-Cbeta domains of the alphabetaTCR. The pre-TCR had a propensity to dimerize in solution, and the molecular envelope of the pre-TCR dimer correlated well with the observed head-to-tail pre-TCR dimer. This mode of pre-TCR dimerization enabled the pre-Talpha domain to interact with the variable (V) beta domain through residues that are highly conserved across the Vbeta and joining (J) beta gene families, thus mimicking the interactions at the core of the alphabetaTCR's Valpha-Vbeta interface. Disruption of this pre-Talpha-Vbeta dimer interface abrogated pre-TCR dimerization in solution and impaired pre-TCR expression on the cell surface. Accordingly, we provide a mechanism of pre-TCR self-association that allows the pre-Talpha chain to simultaneously 'sample' the correct folding of both the V and C domains of any TCR beta-chain, regardless of its ultimate specificity, which represents a critical checkpoint in T-cell development. This unusual dual-chaperone-like sensing function of pre-Talpha represents a unique mechanism in nature whereby developmental quality control regulates the expression and signalling of an integral membrane receptor complex.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pang, Siew Siew -- Berry, Richard -- Chen, Zhenjun -- Kjer-Nielsen, Lars -- Perugini, Matthew A -- King, Glenn F -- Wang, Christina -- Chew, Sock Hui -- La Gruta, Nicole L -- Williams, Neal K -- Beddoe, Travis -- Tiganis, Tony -- Cowieson, Nathan P -- Godfrey, Dale I -- Purcell, Anthony W -- Wilce, Matthew C J -- McCluskey, James -- Rossjohn, Jamie -- England -- Nature. 2010 Oct 14;467(7317):844-8. doi: 10.1038/nature09448.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944746" target="_blank"〉PubMed〈/a〉
    Keywords: Crystallography, X-Ray ; Gene Rearrangement, T-Lymphocyte/genetics ; Humans ; Models, Molecular ; Mutation ; Protein Folding ; *Protein Multimerization ; Protein Structure, Tertiary ; Receptors, Antigen, T-Cell/*chemistry/genetics/*metabolism ; Receptors, Antigen, T-Cell, alpha-beta/chemistry/metabolism ; Signal Transduction ; Solutions ; T-Lymphocytes/cytology/immunology/metabolism
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  • 2
    Publication Date: 2010-02-19
    Description: E1 enzymes activate ubiquitin (Ub) and ubiquitin-like (Ubl) proteins in two steps by carboxy-terminal adenylation and thioester bond formation to a conserved catalytic cysteine in the E1 Cys domain. The structural basis for these intermediates remains unknown. Here we report crystal structures for human SUMO E1 in complex with SUMO adenylate and tetrahedral intermediate analogues at 2.45 and 2.6 A, respectively. These structures show that side chain contacts to ATP.Mg are released after adenylation to facilitate a 130 degree rotation of the Cys domain during thioester bond formation that is accompanied by remodelling of key structural elements including the helix that contains the E1 catalytic cysteine, the crossover and re-entry loops, and refolding of two helices that are required for adenylation. These changes displace side chains required for adenylation with side chains required for thioester bond formation. Mutational and biochemical analyses indicate these mechanisms are conserved in other E1s.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866016/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866016/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Olsen, Shaun K -- Capili, Allan D -- Lu, Xuequan -- Tan, Derek S -- Lima, Christopher D -- F32 GM075695/GM/NIGMS NIH HHS/ -- F32 GM075695-03/GM/NIGMS NIH HHS/ -- R01 AI068038/AI/NIAID NIH HHS/ -- R01 AI068038-02/AI/NIAID NIH HHS/ -- R01 AI068038-03/AI/NIAID NIH HHS/ -- R01 GM065872/GM/NIGMS NIH HHS/ -- R01 GM065872-09/GM/NIGMS NIH HHS/ -- RR-15301/RR/NCRR NIH HHS/ -- England -- Nature. 2010 Feb 18;463(7283):906-12. doi: 10.1038/nature08765.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural Biology, Sloan-Kettering Institute, New York, New York 10065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20164921" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Amino Acid Sequence ; *Biocatalysis ; Catalytic Domain/*physiology ; Conserved Sequence ; Crystallography, X-Ray ; Cysteine/chemistry/metabolism ; Humans ; Magnesium/metabolism ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; SUMO-1 Protein/*chemistry/*metabolism ; Saccharomyces cerevisiae ; Saccharomyces cerevisiae Proteins/metabolism ; Small Ubiquitin-Related Modifier Proteins/metabolism ; Sulfides/*metabolism ; Ubiquitin/metabolism ; Ubiquitin-Activating Enzymes/*chemistry/*metabolism ; Ubiquitins/metabolism
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  • 3
    Publication Date: 2010-07-20
    Description: Chronic myelogenous leukaemia (CML) can progress from a slow growing chronic phase to an aggressive blast crisis phase, but the molecular basis of this transition remains poorly understood. Here we have used mouse models of CML to show that disease progression is regulated by the Musashi-Numb signalling axis. Specifically, we find that the chronic phase is marked by high levels of Numb expression whereas the blast crisis phase has low levels of Numb expression, and that ectopic expression of Numb promotes differentiation and impairs advanced-phase disease in vivo. As a possible explanation for the decreased levels of Numb in the blast crisis phase, we show that NUP98-HOXA9, an oncogene associated with blast crisis CML, can trigger expression of the RNA-binding protein Musashi2 (Msi2), which in turn represses Numb. Notably, loss of Msi2 restores Numb expression and significantly impairs the development and propagation of blast crisis CML in vitro and in vivo. Finally we show that Msi2 expression is not only highly upregulated during human CML progression but is also an early indicator of poorer prognosis. These data show that the Musashi-Numb pathway can control the differentiation of CML cells, and raise the possibility that targeting this pathway may provide a new strategy for the therapy of aggressive leukaemias.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2918284/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2918284/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ito, Takahiro -- Kwon, Hyog Young -- Zimdahl, Bryan -- Congdon, Kendra L -- Blum, Jordan -- Lento, William E -- Zhao, Chen -- Lagoo, Anand -- Gerrard, Gareth -- Foroni, Letizia -- Goldman, John -- Goh, Harriet -- Kim, Soo-Hyun -- Kim, Dong-Wook -- Chuah, Charles -- Oehler, Vivian G -- Radich, Jerald P -- Jordan, Craig T -- Reya, Tannishtha -- AI067798/AI/NIAID NIH HHS/ -- CA122206/CA/NCI NIH HHS/ -- CA140371/CA/NCI NIH HHS/ -- CA18029/CA/NCI NIH HHS/ -- DK072234/DK/NIDDK NIH HHS/ -- DK63031/DK/NIDDK NIH HHS/ -- DP1 CA174422/CA/NCI NIH HHS/ -- DP1 OD006430/OD/NIH HHS/ -- DP1 OD006430-01/OD/NIH HHS/ -- DP1 OD006430-02/OD/NIH HHS/ -- DP1OD006430/OD/NIH HHS/ -- HL097767/HL/NHLBI NIH HHS/ -- P01 CA018029/CA/NCI NIH HHS/ -- R01 CA140371/CA/NCI NIH HHS/ -- R01 DK063031/DK/NIDDK NIH HHS/ -- R01 DK063031-01/DK/NIDDK NIH HHS/ -- R01 DK063031-01S1/DK/NIDDK NIH HHS/ -- R01 DK063031-02/DK/NIDDK NIH HHS/ -- R01 DK063031-03/DK/NIDDK NIH HHS/ -- R01 DK063031-04/DK/NIDDK NIH HHS/ -- R01 DK063031-05/DK/NIDDK NIH HHS/ -- R01 DK063031-06/DK/NIDDK NIH HHS/ -- R01 DK063031-07/DK/NIDDK NIH HHS/ -- R01 DK063031-07S1/DK/NIDDK NIH HHS/ -- R01 DK063031-08/DK/NIDDK NIH HHS/ -- R01 DK072234/DK/NIDDK NIH HHS/ -- R01 DK072234-01A1/DK/NIDDK NIH HHS/ -- R01 DK072234-02/DK/NIDDK NIH HHS/ -- R01 DK072234-03/DK/NIDDK NIH HHS/ -- R01 DK072234-04/DK/NIDDK NIH HHS/ -- R01 HL097767/HL/NHLBI NIH HHS/ -- R01 HL097767-01/HL/NHLBI NIH HHS/ -- R01 HL097767-02/HL/NHLBI NIH HHS/ -- T32 GM007184-33/GM/NIGMS NIH HHS/ -- U19 AI067798/AI/NIAID NIH HHS/ -- U19 AI067798-010006/AI/NIAID NIH HHS/ -- U19 AI067798-020006/AI/NIAID NIH HHS/ -- U19 AI067798-030006/AI/NIAID NIH HHS/ -- U19 AI067798-040006/AI/NIAID NIH HHS/ -- U19 AI067798-050006/AI/NIAID NIH HHS/ -- England -- Nature. 2010 Aug 5;466(7307):765-8. doi: 10.1038/nature09171. Epub 2010 Jul 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20639863" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Blast Crisis/genetics/metabolism/pathology ; *Cell Differentiation/genetics ; Disease Progression ; Fusion Proteins, bcr-abl/genetics/metabolism ; Gene Expression Regulation, Neoplastic ; Homeodomain Proteins/genetics/metabolism ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics/*metabolism/*pathology ; Membrane Proteins/biosynthesis/genetics/metabolism ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins/biosynthesis/genetics/metabolism ; Nuclear Pore Complex Proteins/genetics/metabolism ; Oncogene Proteins, Fusion/genetics/metabolism ; Prognosis ; RNA-Binding Proteins/biosynthesis/genetics/*metabolism ; Receptor, Notch1/metabolism ; Signal Transduction ; Tumor Suppressor Protein p53/metabolism ; Up-Regulation
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  • 4
    Publication Date: 2010-05-14
    Description: The main reason why tumours are not controlled by the immune system is that, unlike pathogens, they do not express potent tumour rejection antigens (TRAs). Tumour vaccination aims at stimulating a systemic immune response targeted to, mostly weak, antigens expressed in the disseminated tumour lesions. Main challenges in developing effective vaccination protocols are the identification of potent and broadly expressed TRAs and effective adjuvants to stimulate a robust and durable immune response. Here we describe an alternative approach in which the expression of new, and thereby potent, antigens are induced in tumour cells by inhibiting nonsense-mediated messenger RNA decay (NMD). Small interfering RNA (siRNA)-mediated inhibition of NMD in tumour cells led to the expression of new antigenic determinants and their immune-mediated rejection. In subcutaneous and metastatic tumour models, tumour-targeted delivery of NMD factor-specific siRNAs conjugated to oligonucleotide aptamer ligands led to significant inhibition of tumour growth that was superior to that of vaccination with granulocyte-macrophage colony-stimulating factor (GM-CSF)-expressing irradiated tumour cells, and could be further enhanced by co-stimulation. Tumour-targeted NMD inhibition forms the basis of a simple, broadly useful, and clinically feasible approach to enhance the antigenicity of disseminated tumours leading to their immune recognition and rejection. The cell-free chemically synthesized oligonucleotide backbone of aptamer-siRNAs reduces the risk of immunogenicity and enhances the feasibility of generating reagents suitable for clinical use.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107067/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107067/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pastor, Fernando -- Kolonias, Despina -- Giangrande, Paloma H -- Gilboa, Eli -- R01 CA138503/CA/NCI NIH HHS/ -- R01 CA151857-02/CA/NCI NIH HHS/ -- England -- Nature. 2010 May 13;465(7295):227-30. doi: 10.1038/nature08999.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology & Immunology, Dodson Interdisciplinary Immunotherapy Institute, University of Miami Miller School of Medicine Miami, Florida 33134, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463739" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, Neoplasm/*genetics/*immunology ; Aptamers, Nucleotide/genetics ; Cancer Vaccines/genetics/immunology/metabolism ; Carrier Proteins/genetics ; Cell Line, Tumor ; Chickens/genetics ; Colonic Neoplasms/*genetics/*immunology/pathology ; Gene Expression Regulation, Neoplastic ; Granulocyte-Macrophage Colony-Stimulating Factor/genetics/metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Nude ; Neoplasm Transplantation ; RNA Interference ; RNA Stability/*genetics ; RNA, Small Interfering/*genetics/therapeutic use ; Xenograft Model Antitumor Assays
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  • 5
    Publication Date: 2010-12-03
    Description: The capacity to fine-tune cellular bioenergetics with the demands of stem-cell maintenance and regeneration is central to normal development and ageing, and to organismal survival during periods of acute stress. How energy metabolism and stem-cell homeostatic processes are coordinated is not well understood. Lkb1 acts as an evolutionarily conserved regulator of cellular energy metabolism in eukaryotic cells and functions as the major upstream kinase to phosphorylate AMP-activated protein kinase (AMPK) and 12 other AMPK-related kinases. Whether Lkb1 regulates stem-cell maintenance remains unknown. Here we show that Lkb1 has an essential role in haematopoietic stem cell (HSC) homeostasis. We demonstrate that ablation of Lkb1 in adult mice results in severe pancytopenia and subsequent lethality. Loss of Lkb1 leads to impaired survival and escape from quiescence of HSCs, resulting in exhaustion of the HSC pool and a marked reduction of HSC repopulating potential in vivo. Lkb1 deletion has an impact on cell proliferation in HSCs, but not on more committed compartments, pointing to context-specific functions for Lkb1 in haematopoiesis. The adverse impact of Lkb1 deletion on haematopoiesis was predominantly cell-autonomous and mTOR complex 1 (mTORC1)-independent, and involves multiple mechanisms converging on mitochondrial apoptosis and possibly downregulation of PGC-1 coactivators and their transcriptional network, which have critical roles in mitochondrial biogenesis and function. Thus, Lkb1 serves as an essential regulator of HSCs and haematopoiesis, and more generally, points to the critical importance of coupling energy metabolism and stem-cell homeostasis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058342/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058342/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gan, Boyi -- Hu, Jian -- Jiang, Shan -- Liu, Yingchun -- Sahin, Ergun -- Zhuang, Li -- Fletcher-Sananikone, Eliot -- Colla, Simona -- Wang, Y Alan -- Chin, Lynda -- Depinho, Ronald A -- 01CA141508/CA/NCI NIH HHS/ -- R21 CA135057/CA/NCI NIH HHS/ -- R21 CA135057-01/CA/NCI NIH HHS/ -- R21CA135057/CA/NCI NIH HHS/ -- U01 CA141508/CA/NCI NIH HHS/ -- U01 CA141508-01/CA/NCI NIH HHS/ -- England -- Nature. 2010 Dec 2;468(7324):701-4. doi: 10.1038/nature09595.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Belfer Institute for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21124456" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Apoptosis ; Cell Cycle/*physiology ; Cell Proliferation ; Cell Survival ; *Energy Metabolism ; Female ; Gene Deletion ; Hematopoiesis ; Hematopoietic Stem Cells/*cytology/*metabolism/pathology ; *Homeostasis ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mitochondria/metabolism/pathology ; Multiprotein Complexes ; Pancytopenia/genetics ; Phenotype ; Protein-Serine-Threonine Kinases/deficiency/genetics/*metabolism ; Proteins/metabolism ; Survival Analysis ; TOR Serine-Threonine Kinases ; Transcription Factors/metabolism
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  • 6
    Publication Date: 2010-05-21
    Description: Type II topoisomerases are required for the management of DNA tangles and supercoils, and are targets of clinical antibiotics and anti-cancer agents. These enzymes catalyse the ATP-dependent passage of one DNA duplex (the transport or T-segment) through a transient, double-stranded break in another (the gate or G-segment), navigating DNA through the protein using a set of dissociable internal interfaces, or 'gates'. For more than 20 years, it has been established that a pair of dimer-related tyrosines, together with divalent cations, catalyse G-segment cleavage. Recent efforts have proposed that strand scission relies on a 'two-metal mechanism', a ubiquitous biochemical strategy that supports vital cellular processes ranging from DNA synthesis to RNA self-splicing. Here we present the structure of the DNA-binding and cleavage core of Saccharomyces cerevisiae topoisomerase II covalently linked to DNA through its active-site tyrosine at 2.5A resolution, revealing for the first time the organization of a cleavage-competent type II topoisomerase configuration. Unexpectedly, metal-soaking experiments indicate that cleavage is catalysed by a novel variation of the classic two-metal approach. Comparative analyses extend this scheme to explain how distantly-related type IA topoisomerases cleave single-stranded DNA, unifying the cleavage mechanisms for these two essential enzyme families. The structure also highlights a hitherto undiscovered allosteric relay that actuates a molecular 'trapdoor' to prevent subunit dissociation during cleavage. This connection illustrates how an indispensable chromosome-disentangling machine auto-regulates DNA breakage to prevent the aberrant formation of mutagenic and cytotoxic genomic lesions.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882514/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882514/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, Bryan H -- Burgin, Alex B -- Deweese, Joseph E -- Osheroff, Neil -- Berger, James M -- CA077373/CA/NCI NIH HHS/ -- GM033944/GM/NIGMS NIH HHS/ -- GM053960/GM/NIGMS NIH HHS/ -- GM08295/GM/NIGMS NIH HHS/ -- R01 CA077373/CA/NCI NIH HHS/ -- R01 CA077373-11S1/CA/NCI NIH HHS/ -- R01 CA077373-12/CA/NCI NIH HHS/ -- R01 GM033944/GM/NIGMS NIH HHS/ -- T32 CA009592/CA/NCI NIH HHS/ -- T32CA09592/CA/NCI NIH HHS/ -- England -- Nature. 2010 Jun 3;465(7298):641-4. doi: 10.1038/nature08974.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20485342" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Base Sequence ; Catalytic Domain ; Crystallography, X-Ray ; DNA/*chemistry/genetics/*metabolism ; DNA Topoisomerases, Type I/*chemistry/*metabolism ; DNA Topoisomerases, Type II/*chemistry/*metabolism ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Saccharomyces cerevisiae/*enzymology ; Tyrosine
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  • 7
    Publication Date: 2010-01-16
    Description: Form I Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase), a complex of eight large (RbcL) and eight small (RbcS) subunits, catalyses the fixation of atmospheric CO(2) in photosynthesis. The limited catalytic efficiency of Rubisco has sparked extensive efforts to re-engineer the enzyme with the goal of enhancing agricultural productivity. To facilitate such efforts we analysed the formation of cyanobacterial form I Rubisco by in vitro reconstitution and cryo-electron microscopy. We show that RbcL subunit folding by the GroEL/GroES chaperonin is tightly coupled with assembly mediated by the chaperone RbcX(2). RbcL monomers remain partially unstable and retain high affinity for GroEL until captured by RbcX(2). As revealed by the structure of a RbcL(8)-(RbcX(2))(8) assembly intermediate, RbcX(2) acts as a molecular staple in stabilizing the RbcL subunits as dimers and facilitates RbcL(8) core assembly. Finally, addition of RbcS results in RbcX(2) release and holoenzyme formation. Specific assembly chaperones may be required more generally in the formation of complex oligomeric structures when folding is closely coupled to assembly.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Cuimin -- Young, Anna L -- Starling-Windhof, Amanda -- Bracher, Andreas -- Saschenbrecker, Sandra -- Rao, Bharathi Vasudeva -- Rao, Karnam Vasudeva -- Berninghausen, Otto -- Mielke, Thorsten -- Hartl, F Ulrich -- Beckmann, Roland -- Hayer-Hartl, Manajit -- England -- Nature. 2010 Jan 14;463(7278):197-202. doi: 10.1038/nature08651.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20075914" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/chemistry/metabolism ; Chaperonin 10/metabolism ; Chaperonin 60/metabolism ; Cryoelectron Microscopy ; Holoenzymes/chemistry/metabolism ; Models, Molecular ; Molecular Chaperones/chemistry/*metabolism ; Protein Binding ; *Protein Folding ; *Protein Multimerization ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Ribulose-Bisphosphate Carboxylase/*chemistry/*metabolism/ultrastructure ; Synechococcus/*chemistry/metabolism
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  • 8
    Publication Date: 2010-01-19
    Description: Influenza A virus, being responsible for seasonal epidemics and reoccurring pandemics, represents a worldwide threat to public health. High mutation rates facilitate the generation of viral escape mutants, rendering vaccines and drugs directed against virus-encoded targets potentially ineffective. In contrast, targeting host cell determinants temporarily dispensable for the host but crucial for virus replication could prevent viral escape. Here we report the discovery of 287 human host cell genes influencing influenza A virus replication in a genome-wide RNA interference (RNAi) screen. Using an independent assay we confirmed 168 hits (59%) inhibiting either the endemic H1N1 (119 hits) or the current pandemic swine-origin (121 hits) influenza A virus strains, with an overlap of 60%. Notably, a subset of these common hits was also essential for replication of a highly pathogenic avian H5N1 strain. In-depth analyses of several factors provided insights into their infection stage relevance. Notably, SON DNA binding protein (SON) was found to be important for normal trafficking of influenza virions to late endosomes early in infection. We also show that a small molecule inhibitor of CDC-like kinase 1 (CLK1) reduces influenza virus replication by more than two orders of magnitude, an effect connected with impaired splicing of the viral M2 messenger RNA. Furthermore, influenza-virus-infected p27(-/-) (cyclin-dependent kinase inhibitor 1B; Cdkn1b) mice accumulated significantly lower viral titres in the lung, providing in vivo evidence for the importance of this gene. Thus, our results highlight the potency of genome-wide RNAi screening for the dissection of virus-host interactions and the identification of drug targets for a broad range of influenza viruses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karlas, Alexander -- Machuy, Nikolaus -- Shin, Yujin -- Pleissner, Klaus-Peter -- Artarini, Anita -- Heuer, Dagmar -- Becker, Daniel -- Khalil, Hany -- Ogilvie, Lesley A -- Hess, Simone -- Maurer, Andre P -- Muller, Elke -- Wolff, Thorsten -- Rudel, Thomas -- Meyer, Thomas F -- England -- Nature. 2010 Feb 11;463(7282):818-22. doi: 10.1038/nature08760. Epub 2010 Jan 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Department, Max Planck Institute for Infection Biology, Chariteplatz 1, 10117 Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20081832" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Factors/genetics/metabolism ; Cell Line ; Cells, Cultured ; Chick Embryo ; Cyclin-Dependent Kinase Inhibitor p27/deficiency/genetics/metabolism ; Epithelial Cells/virology ; Genome, Human/genetics ; *Host-Pathogen Interactions/genetics/physiology ; Humans ; Influenza A Virus, H1N1 Subtype/classification/*growth & development ; Influenza, Human/*genetics/*virology ; Lung/cytology ; Mice ; Mice, Inbred C57BL ; Protein-Serine-Threonine Kinases/genetics ; Protein-Tyrosine Kinases/genetics ; *RNA Interference ; Virus Replication/*physiology
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  • 9
    Publication Date: 2010-05-25
    Description: The three-dimensional structures of proteins often show a modular architecture comprised of discrete structural regions or domains. Cooperative communication between these regions is important for catalysis, regulation and efficient folding; lack of coupling has been implicated in the formation of fibrils and other misfolding pathologies. How different structural regions of a protein communicate and contribute to a protein's overall energetics and folding, however, is still poorly understood. Here we use a single-molecule optical tweezers approach to induce the selective unfolding of particular regions of T4 lysozyme and monitor the effect on other regions not directly acted on by force. We investigate how the topological organization of a protein (the order of structural elements along the sequence) affects the coupling and folding cooperativity between its domains. To probe the status of the regions not directly subjected to force, we determine the free energy changes during mechanical unfolding using Crooks' fluctuation theorem. We pull on topological variants (circular permutants) and find that the topological organization of the polypeptide chain critically determines the folding cooperativity between domains and thus what parts of the folding/unfolding landscape are explored. We speculate that proteins may have evolved to select certain topologies that increase coupling between regions to avoid areas of the landscape that lead to kinetic trapping and misfolding.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2911970/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2911970/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shank, Elizabeth A -- Cecconi, Ciro -- Dill, Jesse W -- Marqusee, Susan -- Bustamante, Carlos -- GM 32543/GM/NIGMS NIH HHS/ -- GM 50945/GM/NIGMS NIH HHS/ -- R01 GM050945/GM/NIGMS NIH HHS/ -- R01 GM050945-17/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jun 3;465(7298):637-40. doi: 10.1038/nature09021. Epub 2010 May 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20495548" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Bacteriophage T4/*enzymology ; Models, Molecular ; Mutant Proteins/chemistry/genetics/metabolism ; Optical Tweezers ; Probability ; Protein Denaturation ; *Protein Folding ; Protein Structure, Tertiary ; Viral Proteins/*chemistry/genetics/*metabolism
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  • 10
    Publication Date: 2010-10-12
    Description: Jasmonates are a family of plant hormones that regulate plant growth, development and responses to stress. The F-box protein CORONATINE INSENSITIVE 1 (COI1) mediates jasmonate signalling by promoting hormone-dependent ubiquitylation and degradation of transcriptional repressor JAZ proteins. Despite its importance, the mechanism of jasmonate perception remains unclear. Here we present structural and pharmacological data to show that the true Arabidopsis jasmonate receptor is a complex of both COI1 and JAZ. COI1 contains an open pocket that recognizes the bioactive hormone (3R,7S)-jasmonoyl-l-isoleucine (JA-Ile) with high specificity. High-affinity hormone binding requires a bipartite JAZ degron sequence consisting of a conserved alpha-helix for COI1 docking and a loop region to trap the hormone in its binding pocket. In addition, we identify a third critical component of the jasmonate co-receptor complex, inositol pentakisphosphate, which interacts with both COI1 and JAZ adjacent to the ligand. Our results unravel the mechanism of jasmonate perception and highlight the ability of F-box proteins to evolve as multi-component signalling hubs.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2988090/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2988090/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sheard, Laura B -- Tan, Xu -- Mao, Haibin -- Withers, John -- Ben-Nissan, Gili -- Hinds, Thomas R -- Kobayashi, Yuichi -- Hsu, Fong-Fu -- Sharon, Michal -- Browse, John -- He, Sheng Yang -- Rizo, Josep -- Howe, Gregg A -- Zheng, Ning -- P30 DK056341/DK/NIDDK NIH HHS/ -- P30 DK056341-10/DK/NIDDK NIH HHS/ -- R01 AI068718/AI/NIAID NIH HHS/ -- R01 AI068718-04/AI/NIAID NIH HHS/ -- R01 CA107134/CA/NCI NIH HHS/ -- R01 CA107134-07/CA/NCI NIH HHS/ -- R01 GM057795/GM/NIGMS NIH HHS/ -- R01 GM057795-12/GM/NIGMS NIH HHS/ -- R01AI068718/AI/NIAID NIH HHS/ -- R01GM57795/GM/NIGMS NIH HHS/ -- T32 GM07270/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Nov 18;468(7322):400-5. doi: 10.1038/nature09430. Epub 2010 Oct 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, Box 357280, University of Washington, Seattle, Washington 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20927106" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Amino Acids/chemistry/metabolism ; Arabidopsis/chemistry/metabolism ; Arabidopsis Proteins/*chemistry/*metabolism ; Binding Sites ; Crystallography, X-Ray ; Cyclopentanes/chemistry/*metabolism ; F-Box Proteins/chemistry/metabolism ; Indenes/chemistry/metabolism ; Inositol Phosphates/*metabolism ; Isoleucine/analogs & derivatives/chemistry/metabolism ; Models, Molecular ; Molecular Sequence Data ; Oxylipins/chemistry/*metabolism ; Peptide Fragments/chemistry/metabolism ; Plant Growth Regulators/chemistry/*metabolism ; Protein Binding ; Protein Structure, Tertiary ; Repressor Proteins/*chemistry/*metabolism ; Signal Transduction
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  • 11
    Publication Date: 2010-02-05
    Description: Photosynthesis makes use of sunlight to convert carbon dioxide into useful biomass and is vital for life on Earth. Crucial components for the photosynthetic process are antenna proteins, which absorb light and transmit the resultant excitation energy between molecules to a reaction centre. The efficiency of these electronic energy transfers has inspired much work on antenna proteins isolated from photosynthetic organisms to uncover the basic mechanisms at play. Intriguingly, recent work has documented that light-absorbing molecules in some photosynthetic proteins capture and transfer energy according to quantum-mechanical probability laws instead of classical laws at temperatures up to 180 K. This contrasts with the long-held view that long-range quantum coherence between molecules cannot be sustained in complex biological systems, even at low temperatures. Here we present two-dimensional photon echo spectroscopy measurements on two evolutionarily related light-harvesting proteins isolated from marine cryptophyte algae, which reveal exceptionally long-lasting excitation oscillations with distinct correlations and anti-correlations even at ambient temperature. These observations provide compelling evidence for quantum-coherent sharing of electronic excitation across the 5-nm-wide proteins under biologically relevant conditions, suggesting that distant molecules within the photosynthetic proteins are 'wired' together by quantum coherence for more efficient light-harvesting in cryptophyte marine algae.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Collini, Elisabetta -- Wong, Cathy Y -- Wilk, Krystyna E -- Curmi, Paul M G -- Brumer, Paul -- Scholes, Gregory D -- England -- Nature. 2010 Feb 4;463(7281):644-7. doi: 10.1038/nature08811.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St George Street, Toronto, Ontario, M5S 3H6 Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20130647" target="_blank"〉PubMed〈/a〉
    Keywords: Algal Proteins/chemistry/metabolism ; Cryptophyta/*metabolism/*radiation effects ; *Light ; Light-Harvesting Protein Complexes/chemistry/metabolism ; Models, Molecular ; Photons ; Photosynthesis/physiology/*radiation effects ; Protein Conformation ; Quantum Theory ; *Temperature
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  • 12
    Publication Date: 2010-06-26
    Description: DNA polymerase eta (Poleta) is unique among eukaryotic polymerases in its proficient ability for error-free replication through ultraviolet-induced cyclobutane pyrimidine dimers, and inactivation of Poleta (also known as POLH) in humans causes the variant form of xeroderma pigmentosum (XPV). We present the crystal structures of Saccharomyces cerevisiae Poleta (also known as RAD30) in ternary complex with a cis-syn thymine-thymine (T-T) dimer and with undamaged DNA. The structures reveal that the ability of Poleta to replicate efficiently through the ultraviolet-induced lesion derives from a simple and yet elegant mechanism, wherein the two Ts of the T-T dimer are accommodated in an active site cleft that is much more open than in other polymerases. We also show by structural, biochemical and genetic analysis that the two Ts are maintained in a stable configuration in the active site via interactions with Gln 55, Arg 73 and Met 74. Together, these features define the basis for Poleta's action on ultraviolet-damaged DNA that is crucial in suppressing the mutagenic and carcinogenic consequences of sun exposure, thereby reducing the incidence of skin cancers in humans.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030469/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030469/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Silverstein, Timothy D -- Johnson, Robert E -- Jain, Rinku -- Prakash, Louise -- Prakash, Satya -- Aggarwal, Aneel K -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 CA107650/CA/NCI NIH HHS/ -- R01 CA107650-39/CA/NCI NIH HHS/ -- R01 ES017767/ES/NIEHS NIH HHS/ -- R01 ES017767-01/ES/NIEHS NIH HHS/ -- England -- Nature. 2010 Jun 24;465(7301):1039-43. doi: 10.1038/nature09104.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural and Chemical Biology, Mount Sinai School of Medicine, Box 1677, 1425 Madison Avenue, New York, New York 10029, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20577207" target="_blank"〉PubMed〈/a〉
    Keywords: Biocatalysis ; Catalytic Domain ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; DNA Damage ; DNA-Directed DNA Polymerase/*chemistry/genetics/*metabolism ; Humans ; Kinetics ; Models, Molecular ; Mutation, Missense ; Nucleic Acid Conformation ; Protein Structure, Tertiary ; Pyrimidine Dimers/chemistry/metabolism ; Saccharomyces cerevisiae/*enzymology/genetics ; Skin Neoplasms/*enzymology/genetics ; Structure-Activity Relationship ; Xeroderma Pigmentosum/enzymology/genetics
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  • 13
    Publication Date: 2010-10-01
    Description: RANK ligand (RANKL), a TNF-related molecule, is essential for osteoclast formation, function and survival through interaction with its receptor RANK. Mammary glands of RANK- and RANKL-deficient mice develop normally during sexual maturation, but fail to form lobuloalveolar structures during pregnancy because of defective proliferation and increased apoptosis of mammary epithelium. It has been shown that RANKL is responsible for the major proliferative response of mouse mammary epithelium to progesterone during mammary lactational morphogenesis, and in mouse models, manipulated to induce activation of the RANK/RANKL pathway in the absence of strict hormonal control, inappropriate mammary proliferation is observed. However, there is no evidence so far of a functional contribution of RANKL to tumorigenesis. Here we show that RANK and RANKL are expressed within normal, pre-malignant and neoplastic mammary epithelium, and using complementary gain-of-function (mouse mammary tumour virus (MMTV)-RANK transgenic mice) and loss-of function (pharmacological inhibition of RANKL) approaches, define a direct contribution of this pathway in mammary tumorigenesis. Accelerated pre-neoplasias and increased mammary tumour formation were observed in MMTV-RANK transgenic mice after multiparity or treatment with carcinogen and hormone (progesterone). Reciprocally, selective pharmacological inhibition of RANKL attenuated mammary tumour development not only in hormone- and carcinogen-treated MMTV-RANK and wild-type mice, but also in the MMTV-neu transgenic spontaneous tumour model. The reduction in tumorigenesis upon RANKL inhibition was preceded by a reduction in pre-neoplasias as well as rapid and sustained reductions in hormone- and carcinogen-induced mammary epithelial proliferation and cyclin D1 levels. Collectively, our results indicate that RANKL inhibition is acting directly on hormone-induced mammary epithelium at early stages in tumorigenesis, and the permissive contribution of progesterone to increased mammary cancer incidence is due to RANKL-dependent proliferative changes in the mammary epithelium. The current study highlights a potential role for RANKL inhibition in the management of proliferative breast disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gonzalez-Suarez, Eva -- Jacob, Allison P -- Jones, Jon -- Miller, Robert -- Roudier-Meyer, Martine P -- Erwert, Ryan -- Pinkas, Jan -- Branstetter, Dan -- Dougall, William C -- England -- Nature. 2010 Nov 4;468(7320):103-7. doi: 10.1038/nature09495. Epub 2010 Sep 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Hematology/Oncology Research, Amgen Inc, Seattle, Washington 98119, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20881963" target="_blank"〉PubMed〈/a〉
    Keywords: 9,10-Dimethyl-1,2-benzanthracene/administration & dosage/adverse effects ; Animals ; Breast Neoplasms/metabolism/pathology ; Cell Proliferation/drug effects ; Cell Transformation, Neoplastic/*chemically induced/*drug effects/pathology ; Disease Models, Animal ; Epithelial Cells/drug effects/metabolism/pathology ; Female ; Humans ; Lung Neoplasms/secondary ; Mammary Neoplasms, Experimental/*chemically ; induced/genetics/metabolism/*pathology ; Mammary Tumor Virus, Mouse/genetics/physiology ; Medroxyprogesterone Acetate/administration & dosage/adverse effects ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Neoplasm Invasiveness ; Precancerous Conditions/pathology/prevention & control ; Progesterone/administration & dosage/adverse effects ; Progestins/administration & dosage/*adverse effects ; RANK Ligand/antagonists & inhibitors/genetics/*metabolism ; Receptor Activator of Nuclear Factor-kappa B/genetics/metabolism
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  • 14
    Publication Date: 2010-10-12
    Description: Reciprocity of inflammation, oxidative stress and neovascularization is emerging as an important mechanism underlying numerous processes from tissue healing and remodelling to cancer progression. Whereas the mechanism of hypoxia-driven angiogenesis is well understood, the link between inflammation-induced oxidation and de novo blood vessel growth remains obscure. Here we show that the end products of lipid oxidation, omega-(2-carboxyethyl)pyrrole (CEP) and other related pyrroles, are generated during inflammation and wound healing and accumulate at high levels in ageing tissues in mice and in highly vascularized tumours in both murine and human melanoma. The molecular patterns of carboxyalkylpyrroles are recognized by Toll-like receptor 2 (TLR2), but not TLR4 or scavenger receptors on endothelial cells, leading to an angiogenic response that is independent of vascular endothelial growth factor. CEP promoted angiogenesis in hindlimb ischaemia and wound healing models through MyD88-dependent TLR2 signalling. Neutralization of endogenous carboxyalkylpyrroles impaired wound healing and tissue revascularization and diminished tumour angiogenesis. Both TLR2 and MyD88 are required for CEP-induced stimulation of Rac1 and endothelial migration. Taken together, these findings establish a new function of TLR2 as a sensor of oxidation-associated molecular patterns, providing a key link connecting inflammation, oxidative stress, innate immunity and angiogenesis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990914/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990914/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉West, Xiaoxia Z -- Malinin, Nikolay L -- Merkulova, Alona A -- Tischenko, Mira -- Kerr, Bethany A -- Borden, Ernest C -- Podrez, Eugene A -- Salomon, Robert G -- Byzova, Tatiana V -- CA126847/CA/NCI NIH HHS/ -- GM021249/GM/NIGMS NIH HHS/ -- HL071625/HL/NHLBI NIH HHS/ -- HL073311/HL/NHLBI NIH HHS/ -- HL077213/HL/NHLBI NIH HHS/ -- R01 HL071625/HL/NHLBI NIH HHS/ -- R01 HL071625-07/HL/NHLBI NIH HHS/ -- R01 HL071625-08/HL/NHLBI NIH HHS/ -- R01 HL077213/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Oct 21;467(7318):972-6. doi: 10.1038/nature09421. Epub 2010 Oct 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Cardiology, J. J. Jacobs Center for Thrombosis and Vascular Biology, NB50, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20927103" target="_blank"〉PubMed〈/a〉
    Keywords: Aging/metabolism ; Animals ; Antigens, CD31/metabolism ; Aorta/cytology/drug effects ; Cell Line ; Cell Movement ; Endothelial Cells/metabolism ; Hindlimb/metabolism ; Humans ; Immunity, Innate/immunology ; Inflammation/metabolism ; Ischemia/metabolism ; Ligands ; Melanoma/blood supply/metabolism ; Mice ; Mice, Inbred C57BL ; Myeloid Differentiation Factor 88/metabolism ; Neovascularization, Pathologic/*metabolism ; *Neovascularization, Physiologic/drug effects ; Oxidation-Reduction ; Oxidative Stress/*physiology ; Propionates ; Pyrroles/chemistry/*metabolism/pharmacology ; Receptors, Scavenger/metabolism ; Signal Transduction/drug effects ; Toll-Like Receptor 2/agonists/*metabolism ; Toll-Like Receptor 4/metabolism ; Vascular Endothelial Growth Factor A/metabolism ; Wound Healing/drug effects/physiology ; rac1 GTP-Binding Protein/metabolism
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  • 15
    Publication Date: 2010-10-12
    Description: Blood pressure is critically controlled by angiotensins, which are vasopressor peptides specifically released by the enzyme renin from the tail of angiotensinogen-a non-inhibitory member of the serpin family of protease inhibitors. Although angiotensinogen has long been regarded as a passive substrate, the crystal structures solved here to 2.1 A resolution show that the angiotensin cleavage site is inaccessibly buried in its amino-terminal tail. The conformational rearrangement that makes this site accessible for proteolysis is revealed in our 4.4 A structure of the complex of human angiotensinogen with renin. The co-ordinated changes involved are seen to be critically linked by a conserved but labile disulphide bridge. Here we show that the reduced unbridged form of angiotensinogen is present in the circulation in a near 40:60 ratio with the oxidized sulphydryl-bridged form, which preferentially interacts with receptor-bound renin. We propose that this redox-responsive transition of angiotensinogen to a form that will more effectively release angiotensin at a cellular level contributes to the modulation of blood pressure. Specifically, we demonstrate the oxidative switch of angiotensinogen to its more active sulphydryl-bridged form in the maternal circulation in pre-eclampsia-the hypertensive crisis of pregnancy that threatens the health and survival of both mother and child.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3024006/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3024006/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, Aiwu -- Carrell, Robin W -- Murphy, Michael P -- Wei, Zhenquan -- Yan, Yahui -- Stanley, Peter L D -- Stein, Penelope E -- Broughton Pipkin, Fiona -- Read, Randy J -- 082961/Wellcome Trust/United Kingdom -- BS/05/002/18361/British Heart Foundation/United Kingdom -- MC_U105663142/Medical Research Council/United Kingdom -- PG/08/041/24818/British Heart Foundation/United Kingdom -- PG/09/072/27945/British Heart Foundation/United Kingdom -- British Heart Foundation/United Kingdom -- Medical Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Nov 4;468(7320):108-11. doi: 10.1038/nature09505. Epub 2010 Oct 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK. awz20@cam.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20927107" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Angiotensinogen/blood/*chemistry/*metabolism ; Angiotensins/chemistry/*metabolism/secretion ; Blood Pressure ; Crystallography, X-Ray ; Disulfides/chemistry/metabolism ; Female ; Humans ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Oxidation-Reduction ; Oxidative Stress ; Pre-Eclampsia/blood/metabolism ; Pregnancy ; Protein Conformation ; *Protein Processing, Post-Translational ; Renin/chemistry/metabolism
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  • 16
    Publication Date: 2010-09-25
    Description: Gram-negative bacteria, such as Escherichia coli, frequently use tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel various toxic compounds from the cell. The efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. No previous structural information was available for the heavy-metal efflux (HME) subfamily of the RND efflux pumps. Here we describe the crystal structures of the inner-membrane transporter CusA in the absence and presence of bound Cu(I) or Ag(I). These CusA structures provide new structural information about the HME subfamily of RND efflux pumps. The structures suggest that the metal-binding sites, formed by a three-methionine cluster, are located within the cleft region of the periplasmic domain. This cleft is closed in the apo-CusA form but open in the CusA-Cu(I) and CusA-Ag(I) structures, which directly suggests a plausible pathway for ion export. Binding of Cu(I) and Ag(I) triggers significant conformational changes in both the periplasmic and transmembrane domains. The crystal structure indicates that CusA has, in addition to the three-methionine metal-binding site, four methionine pairs-three located in the transmembrane region and one in the periplasmic domain. Genetic analysis and transport assays suggest that CusA is capable of actively picking up metal ions from the cytosol, using these methionine pairs or clusters to bind and export metal ions. These structures suggest a stepwise shuttle mechanism for transport between these sites.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946090/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946090/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Long, Feng -- Su, Chih-Chia -- Zimmermann, Michael T -- Boyken, Scott E -- Rajashankar, Kanagalaghatta R -- Jernigan, Robert L -- Yu, Edward W -- GM 072014/GM/NIGMS NIH HHS/ -- GM 074027/GM/NIGMS NIH HHS/ -- GM 081680/GM/NIGMS NIH HHS/ -- GM 086431/GM/NIGMS NIH HHS/ -- R01 GM072014/GM/NIGMS NIH HHS/ -- R01 GM074027/GM/NIGMS NIH HHS/ -- R01 GM074027-05/GM/NIGMS NIH HHS/ -- R01 GM086431/GM/NIGMS NIH HHS/ -- R01 GM086431-01A2/GM/NIGMS NIH HHS/ -- RR-15301/RR/NCRR NIH HHS/ -- England -- Nature. 2010 Sep 23;467(7314):484-8. doi: 10.1038/nature09395.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular, Cellular and Developmental Biology Interdepartmental Graduate Program, Iowa State University, Iowa 50011, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20865003" target="_blank"〉PubMed〈/a〉
    Keywords: Apoproteins/chemistry/metabolism ; Binding Sites ; Cell Membrane/metabolism ; Copper/chemistry/*metabolism ; Crystallography, X-Ray ; Cytosol/metabolism ; Escherichia coli/*chemistry ; Escherichia coli Proteins/*chemistry/*metabolism ; Ion Transport ; Membrane Transport Proteins/*chemistry/*metabolism ; Methionine/*metabolism ; Models, Biological ; Models, Molecular ; Periplasm/metabolism ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Silver/chemistry/*metabolism ; Structure-Activity Relationship
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  • 17
    Publication Date: 2010-09-30
    Description: Cell-cell signalling of semaphorin ligands through interaction with plexin receptors is important for the homeostasis and morphogenesis of many tissues and is widely studied for its role in neural connectivity, cancer, cell migration and immune responses. SEMA4D and Sema6A exemplify two diverse vertebrate, membrane-spanning semaphorin classes (4 and 6) that are capable of direct signalling through members of the two largest plexin classes, B and A, respectively. In the absence of any structural information on the plexin ectodomain or its interaction with semaphorins the extracellular specificity and mechanism controlling plexin signalling has remained unresolved. Here we present crystal structures of cognate complexes of the semaphorin-binding regions of plexins B1 and A2 with semaphorin ectodomains (human PLXNB1(1-2)-SEMA4D(ecto) and murine PlxnA2(1-4)-Sema6A(ecto)), plus unliganded structures of PlxnA2(1-4) and Sema6A(ecto). These structures, together with biophysical and cellular assays of wild-type and mutant proteins, reveal that semaphorin dimers independently bind two plexin molecules and that signalling is critically dependent on the avidity of the resulting bivalent 2:2 complex (monomeric semaphorin binds plexin but fails to trigger signalling). In combination, our data favour a cell-cell signalling mechanism involving semaphorin-stabilized plexin dimerization, possibly followed by clustering, which is consistent with previous functional data. Furthermore, the shared generic architecture of the complexes, formed through conserved contacts of the amino-terminal seven-bladed beta-propeller (sema) domains of both semaphorin and plexin, suggests that a common mode of interaction triggers all semaphorin-plexin based signalling, while distinct insertions within or between blades of the sema domains determine binding specificity.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3587840/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3587840/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Janssen, Bert J C -- Robinson, Ross A -- Perez-Branguli, Francesc -- Bell, Christian H -- Mitchell, Kevin J -- Siebold, Christian -- Jones, E Yvonne -- 082301/Wellcome Trust/United Kingdom -- 083111/Wellcome Trust/United Kingdom -- 10976/Cancer Research UK/United Kingdom -- A10976/Cancer Research UK/United Kingdom -- A3964/Cancer Research UK/United Kingdom -- A5261/Cancer Research UK/United Kingdom -- G0700232/Medical Research Council/United Kingdom -- G0700232(82098)/Medical Research Council/United Kingdom -- G0900084/Medical Research Council/United Kingdom -- G9900061/Medical Research Council/United Kingdom -- G9900061(69203)/Medical Research Council/United Kingdom -- Cancer Research UK/United Kingdom -- Medical Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Oct 28;467(7319):1118-22. doi: 10.1038/nature09468. Epub 2010 Sep 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20877282" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, CD/chemistry/genetics/metabolism ; Binding Sites ; Cell Adhesion Molecules/*chemistry/genetics/*metabolism ; Cell Communication ; Crystallography, X-Ray ; Humans ; Ligands ; Mice ; Mice, Inbred C57BL ; Models, Molecular ; NIH 3T3 Cells ; Nerve Tissue Proteins/*chemistry/genetics/*metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Cell Surface/chemistry/genetics/metabolism ; Semaphorins/*chemistry/genetics/*metabolism ; *Signal Transduction ; Structure-Activity Relationship
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  • 18
    Publication Date: 2010-06-26
    Description: Lymph nodes (LNs) capture microorganisms that breach the body's external barriers and enter draining lymphatics, limiting the systemic spread of pathogens. Recent work has shown that CD11b(+)CD169(+) macrophages, which populate the subcapsular sinus (SCS) of LNs, are critical for the clearance of viruses from the lymph and for initiating antiviral humoral immune responses. Here we show, using vesicular stomatitis virus (VSV), a relative of rabies virus transmitted by insect bites, that SCS macrophages perform a third vital function: they prevent lymph-borne neurotropic viruses from infecting the central nervous system (CNS). On local depletion of LN macrophages, about 60% of mice developed ascending paralysis and died 7-10 days after subcutaneous infection with a small dose of VSV, whereas macrophage-sufficient animals remained asymptomatic and cleared the virus. VSV gained access to the nervous system through peripheral nerves in macrophage-depleted LNs. In contrast, within macrophage-sufficient LNs VSV replicated preferentially in SCS macrophages but not in adjacent nerves. Removal of SCS macrophages did not compromise adaptive immune responses against VSV, but decreased type I interferon (IFN-I) production within infected LNs. VSV-infected macrophages recruited IFN-I-producing plasmacytoid dendritic cells to the SCS and in addition were a major source of IFN-I themselves. Experiments in bone marrow chimaeric mice revealed that IFN-I must act on both haematopoietic and stromal compartments, including the intranodal nerves, to prevent lethal infection with VSV. These results identify SCS macrophages as crucial gatekeepers to the CNS that prevent fatal viral invasion of the nervous system on peripheral infection.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892812/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892812/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Iannacone, Matteo -- Moseman, E Ashley -- Tonti, Elena -- Bosurgi, Lidia -- Junt, Tobias -- Henrickson, Sarah E -- Whelan, Sean P -- Guidotti, Luca G -- von Andrian, Ulrich H -- AI069259/AI/NIAID NIH HHS/ -- AI072252/AI/NIAID NIH HHS/ -- AI078897/AI/NIAID NIH HHS/ -- AR42689/AR/NIAMS NIH HHS/ -- P01 AI078897/AI/NIAID NIH HHS/ -- P01 AI078897-01/AI/NIAID NIH HHS/ -- P01 CA071932/CA/NCI NIH HHS/ -- P01 CA071932-12S29003/CA/NCI NIH HHS/ -- R01 AI069259/AI/NIAID NIH HHS/ -- R01 AI069259-06/AI/NIAID NIH HHS/ -- R01 AI072252/AI/NIAID NIH HHS/ -- R01 AI072252-04/AI/NIAID NIH HHS/ -- T32 GM007753/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jun 24;465(7301):1079-83. doi: 10.1038/nature09118.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Immune Disease Institute and Department of Pathology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA. Matteo_Iannacone@hms.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20577213" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Central Nervous System/cytology/*immunology/*virology ; Dendritic Cells/immunology ; Injections ; Interferon Type I/immunology ; Lymph Nodes/cytology/*immunology/innervation/*virology ; Macrophages/*immunology/virology ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Paralysis/complications/virology ; Peripheral Nerves/virology ; Receptor, Interferon alpha-beta/deficiency ; Rhabdoviridae Infections/complications/*immunology/virology ; Survival Rate ; Vesicular stomatitis Indiana virus/immunology/pathogenicity/physiology ; Vesicular stomatitis New Jersey virus/immunology/pathogenicity/physiology ; Vesiculovirus/*immunology/pathogenicity/physiology
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  • 19
    Publication Date: 2010-04-16
    Description: Tumour metastasis is the primary cause of death of cancer patients. Development of new therapeutics preventing tumour metastasis is urgently needed. Migrastatin is a natural product secreted by Streptomyces, and synthesized migrastatin analogues such as macroketone are potent inhibitors of metastatic tumour cell migration, invasion and metastasis. Here we show that these migrastatin analogues target the actin-bundling protein fascin to inhibit its activity. X-ray crystal structural studies reveal that migrastatin analogues bind to one of the actin-binding sites on fascin. Our data demonstrate that actin cytoskeletal proteins such as fascin can be explored as new molecular targets for cancer treatment, in a similar manner to the microtubule protein tubulin.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2857318/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2857318/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Lin -- Yang, Shengyu -- Jakoncic, Jean -- Zhang, J Jillian -- Huang, Xin-Yun -- CA136837/CA/NCI NIH HHS/ -- R01 CA136837/CA/NCI NIH HHS/ -- R01 CA136837-01A1/CA/NCI NIH HHS/ -- England -- Nature. 2010 Apr 15;464(7291):1062-6. doi: 10.1038/nature08978.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, Cornell University Weill Medical College, New York, New York 10065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20393565" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/metabolism ; Animals ; Antineoplastic Agents/chemistry/metabolism/pharmacology/therapeutic use ; Binding Sites/drug effects ; Breast Neoplasms/drug therapy/pathology ; Carrier Proteins/*antagonists & inhibitors/chemistry/genetics/metabolism ; Cell Line, Tumor ; Cell Movement/drug effects ; Crystallography, X-Ray ; Drug Resistance, Neoplasm/genetics ; Female ; Humans ; Lung Neoplasms/prevention & control/secondary ; Macrolides/*chemistry/metabolism/*pharmacology/therapeutic use ; Mice ; Mice, Inbred BALB C ; Mice, Inbred NOD ; Mice, SCID ; Microfilament Proteins/*antagonists & inhibitors/chemistry/genetics/metabolism ; Models, Molecular ; Mutation/genetics ; Neoplasm Invasiveness/pathology/prevention & control ; Neoplasm Metastasis/drug therapy/pathology/*prevention & control ; Piperidones/*chemistry/metabolism/*pharmacology/therapeutic use ; Protein Conformation
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  • 20
    Publication Date: 2010-12-24
    Description: Neurotransmitter/sodium symporters (NSSs) couple the uptake of neurotransmitter with one or more sodium ions, removing neurotransmitter from the synaptic cleft. NSSs are essential to the function of chemical synapses, are associated with multiple neurological diseases and disorders, and are the targets of therapeutic and illicit drugs. LeuT, a prokaryotic orthologue of the NSS family, is a model transporter for understanding the relationships between molecular mechanism and atomic structure in a broad range of sodium-dependent and sodium-independent secondary transporters. At present there is a controversy over whether there are one or two high-affinity substrate binding sites in LeuT. The first-reported crystal structure of LeuT, together with subsequent functional and structural studies, provided direct evidence for a single, high-affinity, centrally located substrate-binding site, defined as the S1 site. Recent binding, flux and molecular simulation studies, however, have been interpreted in terms of a model where there are two high-affinity binding sites: the central, S1, site and a second, the S2 site, located within the extracellular vestibule. Furthermore, it was proposed that the S1 and S2 sites are allosterically coupled such that occupancy of the S2 site is required for the cytoplasmic release of substrate from the S1 site. Here we address this controversy by performing direct measurement of substrate binding to wild-type LeuT and to S2 site mutants using isothermal titration calorimetry, equilibrium dialysis and scintillation proximity assays. In addition, we perform uptake experiments to determine whether the proposed allosteric coupling between the putative S2 site and the S1 site manifests itself in the kinetics of substrate flux. We conclude that LeuT harbours a single, centrally located, high-affinity substrate-binding site and that transport is well described by a simple, single-substrate kinetic mechanism.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079577/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079577/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Piscitelli, Chayne L -- Krishnamurthy, Harini -- Gouaux, Eric -- R37 MH070039/MH/NIMH NIH HHS/ -- R37 MH070039-07/MH/NIMH NIH HHS/ -- R37 MH070039-08/MH/NIMH NIH HHS/ -- T32 DK007680/DK/NIDDK NIH HHS/ -- T32 DK007680-17/DK/NIDDK NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Dec 23;468(7327):1129-32. doi: 10.1038/nature09581.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21179170" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Humans ; Ionophores/pharmacology ; Kinetics ; Leucine/genetics ; Models, Molecular ; Mutation ; Plasma Membrane Neurotransmitter Transport ; Proteins/*chemistry/genetics/*metabolism ; Protein Transport/drug effects ; Valinomycin/pharmacology
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  • 21
    Publication Date: 2010-07-16
    Description: The translocation step of protein synthesis entails large-scale rearrangements of the ribosome-transfer RNA (tRNA) complex. Here we have followed tRNA movement through the ribosome during translocation by time-resolved single-particle electron cryomicroscopy (cryo-EM). Unbiased computational sorting of cryo-EM images yielded 50 distinct three-dimensional reconstructions, showing the tRNAs in classical, hybrid and various novel intermediate states that provide trajectories and kinetic information about tRNA movement through the ribosome. The structures indicate how tRNA movement is coupled with global and local conformational changes of the ribosome, in particular of the head and body of the small ribosomal subunit, and show that dynamic interactions between tRNAs and ribosomal residues confine the path of the tRNAs through the ribosome. The temperature dependence of ribosome dynamics reveals a surprisingly flat energy landscape of conformational variations at physiological temperature. The ribosome functions as a Brownian machine that couples spontaneous conformational changes driven by thermal energy to directed movement.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fischer, Niels -- Konevega, Andrey L -- Wintermeyer, Wolfgang -- Rodnina, Marina V -- Stark, Holger -- England -- Nature. 2010 Jul 15;466(7304):329-33. doi: 10.1038/nature09206.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉3D Electron Cryomicroscopy Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Gottingen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20631791" target="_blank"〉PubMed〈/a〉
    Keywords: Cryoelectron Microscopy ; Escherichia coli ; Kinetics ; Models, Molecular ; Molecular Conformation ; *Movement ; *Protein Biosynthesis ; RNA, Transfer/genetics/*metabolism ; Ribosome Subunits, Large, Bacterial/chemistry/metabolism ; Ribosome Subunits, Small, Bacterial/chemistry/metabolism ; Ribosomes/chemistry/*metabolism ; Temperature ; Thermodynamics ; Time Factors
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  • 22
    Publication Date: 2010-07-09
    Description: Interconversion between conductive and non-conductive forms of the K(+) channel selectivity filter underlies a variety of gating events, from flicker transitions (at the microsecond timescale) to C-type inactivation (millisecond to second timescale). Here we report the crystal structure of the Streptomyces lividans K(+) channel KcsA in its open-inactivated conformation and investigate the mechanism of C-type inactivation gating at the selectivity filter from channels 'trapped' in a series of partially open conformations. Five conformer classes were identified with openings ranging from 12 A in closed KcsA (Calpha-Calpha distances at Thr 112) to 32 A when fully open. They revealed a remarkable correlation between the degree of gate opening and the conformation and ion occupancy of the selectivity filter. We show that a gradual filter backbone reorientation leads first to a loss of the S2 ion binding site and a subsequent loss of the S3 binding site, presumably abrogating ion conduction. These structures indicate a molecular basis for C-type inactivation in K(+) channels.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033749/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033749/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuello, Luis G -- Jogini, Vishwanath -- Cortes, D Marien -- Perozo, Eduardo -- R01 GM057846/GM/NIGMS NIH HHS/ -- R01 GM057846-15/GM/NIGMS NIH HHS/ -- R01-GM57846/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jul 8;466(7303):203-8. doi: 10.1038/nature09153.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, University of Chicago, Illinois 60637, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20613835" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*antagonists & inhibitors/*chemistry/metabolism ; Binding Sites ; Crystallography, X-Ray ; Electrons ; *Ion Channel Gating ; Kinetics ; Models, Biological ; Models, Molecular ; Potassium/metabolism ; Potassium Channels/*chemistry/metabolism ; Protein Conformation ; Streptomyces lividans/*chemistry ; Structure-Activity Relationship
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  • 23
    Publication Date: 2010-04-30
    Description: In sensory cortex regions, neurons are tuned to specific stimulus features. For example, in the visual cortex, many neurons fire predominantly in response to moving objects of a preferred orientation. However, the characteristics of the synaptic input that cortical neurons receive to generate their output firing pattern remain unclear. Here we report a novel approach for the visualization and functional mapping of sensory inputs to the dendrites of cortical neurons in vivo. By combining high-speed two-photon imaging with electrophysiological recordings, we identify local subthreshold calcium signals that correspond to orientation-specific synaptic inputs. We find that even inputs that share the same orientation preference are widely distributed throughout the dendritic tree. At the same time, inputs of different orientation preference are interspersed, so that adjacent dendritic segments are tuned to distinct orientations. Thus, orientation-tuned neurons can compute their characteristic firing pattern by integrating spatially distributed synaptic inputs coding for multiple stimulus orientations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jia, Hongbo -- Rochefort, Nathalie L -- Chen, Xiaowei -- Konnerth, Arthur -- England -- Nature. 2010 Apr 29;464(7293):1307-12. doi: 10.1038/nature08947.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Neuroscience and Center for Integrated Protein Science, Technical University Munich, Biedersteinerstrasse 29, 80802 Munich, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20428163" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Calcium Signaling ; Dendrites/*physiology ; Mice ; Mice, Inbred C57BL ; Models, Neurological ; Sensory Receptor Cells/cytology/*physiology ; Synapses/metabolism ; Visual Cortex/*cytology
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  • 24
    Publication Date: 2010-10-01
    Description: In most bacteria and all archaea, glutamyl-tRNA synthetase (GluRS) glutamylates both tRNA(Glu) and tRNA(Gln), and then Glu-tRNA(Gln) is selectively converted to Gln-tRNA(Gln) by a tRNA-dependent amidotransferase. The mechanisms by which the two enzymes recognize their substrate tRNA(s), and how they cooperate with each other in Gln-tRNA(Gln) synthesis, remain to be determined. Here we report the formation of the 'glutamine transamidosome' from the bacterium Thermotoga maritima, consisting of tRNA(Gln), GluRS and the heterotrimeric amidotransferase GatCAB, and its crystal structure at 3.35 A resolution. The anticodon-binding body of GluRS recognizes the common features of tRNA(Gln) and tRNA(Glu), whereas the tail body of GatCAB recognizes the outer corner of the L-shaped tRNA(Gln) in a tRNA(Gln)-specific manner. GluRS is in the productive form, as its catalytic body binds to the amino-acid-acceptor arm of tRNA(Gln). In contrast, GatCAB is in the non-productive form: the catalytic body of GatCAB contacts that of GluRS and is located near the acceptor stem of tRNA(Gln), in an appropriate site to wait for the completion of Glu-tRNA(Gln) formation by GluRS. We identified the hinges between the catalytic and anticodon-binding bodies of GluRS and between the catalytic and tail bodies of GatCAB, which allow both GluRS and GatCAB to adopt the productive and non-productive forms. The catalytic bodies of the two enzymes compete for the acceptor arm of tRNA(Gln) and therefore cannot assume their productive forms simultaneously. The transition from the present glutamylation state, with the productive GluRS and the non-productive GatCAB, to the putative amidation state, with the non-productive GluRS and the productive GatCAB, requires an intermediate state with the two enzymes in their non-productive forms, for steric reasons. The proposed mechanism explains how the transamidosome efficiently performs the two consecutive steps of Gln-tRNA(Gln) formation, with a low risk of releasing the unstable intermediate Glu-tRNA(Gln).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ito, Takuhiro -- Yokoyama, Shigeyuki -- England -- Nature. 2010 Sep 30;467(7315):612-6. doi: 10.1038/nature09411.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20882017" target="_blank"〉PubMed〈/a〉
    Keywords: Anticodon/genetics ; Biocatalysis ; Crystallography, X-Ray ; Electrophoretic Mobility Shift Assay ; Glutamate-tRNA Ligase/*chemistry/*metabolism ; Models, Molecular ; Molecular Conformation ; Nitrogenous Group Transferases/*chemistry/*metabolism ; Protein Binding ; RNA, Transfer, Gln/biosynthesis/*chemistry/*metabolism ; RNA, Transfer, Glu/chemistry/metabolism ; Staphylococcus aureus/enzymology ; Substrate Specificity ; Thermotoga maritima/*enzymology
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  • 25
    Publication Date: 2010-07-24
    Description: Learning new action sequences subserves a plethora of different abilities such as escaping a predator, playing the piano, or producing fluent speech. Proper initiation and termination of each action sequence is critical for the organization of behaviour, and is compromised in nigrostriatal disorders like Parkinson's and Huntington's diseases. Using a self-paced operant task in which mice learn to perform a particular sequence of actions to obtain an outcome, we found neural activity in nigrostriatal circuits specifically signalling the initiation or the termination of each action sequence. This start/stop activity emerged during sequence learning, was specific for particular actions, and did not reflect interval timing, movement speed or action value. Furthermore, genetically altering the function of striatal circuits disrupted the development of start/stop activity and selectively impaired sequence learning. These results have important implications for understanding the functional organization of actions and the sequence initiation and termination impairments observed in basal ganglia disorders.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477867/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477867/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jin, Xin -- Costa, Rui M -- 243393/European Research Council/International -- Z01 AA000416-02/Intramural NIH HHS/ -- England -- Nature. 2010 Jul 22;466(7305):457-62. doi: 10.1038/nature09263.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Bethesda, Maryland 20892-9412, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20651684" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Behavior, Animal/physiology ; Dopamine/metabolism ; Glutamic Acid/metabolism ; Learning/*physiology ; Male ; Mice ; Mice, Inbred C57BL ; Models, Neurological ; Neostriatum/*physiology ; Neural Pathways/*physiology ; Receptors, N-Methyl-D-Aspartate/deficiency/genetics/metabolism ; Substantia Nigra/*physiology
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  • 26
    Publication Date: 2010-04-30
    Description: The interferon-inducible dynamin-like myxovirus resistance protein 1 (MxA; also called MX1) GTPase is a key mediator of cell-autonomous innate immunity against pathogens such as influenza viruses. MxA partially localizes to COPI-positive membranes of the smooth endoplasmic reticulum-Golgi intermediate compartment. At the point of infection, it redistributes to sites of viral replication and promotes missorting of essential viral constituents. It has been proposed that the middle domain and the GTPase effector domain of dynamin-like GTPases constitute a stalk that mediates oligomerization and transmits conformational changes from the G domain to the target structure; however, the molecular architecture of this stalk has remained elusive. Here we report the crystal structure of the stalk of human MxA, which folds into a four-helical bundle. This structure tightly oligomerizes in the crystal in a criss-cross pattern involving three distinct interfaces and one loop. Mutations in each of these interaction sites interfere with native assembly, oligomerization, membrane binding and antiviral activity of MxA. On the basis of these results, we propose a structural model for dynamin oligomerization and stimulated GTP hydrolysis that is consistent with previous structural predictions and has functional implications for all members of the dynamin family.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gao, Song -- von der Malsburg, Alexander -- Paeschke, Susann -- Behlke, Joachim -- Haller, Otto -- Kochs, Georg -- Daumke, Oliver -- England -- Nature. 2010 May 27;465(7297):502-6. doi: 10.1038/nature08972. Epub 2010 Apr 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Delbruck-Centrum for Molecular Medicine, Crystallography, Robert-Rossle-Strasse 10, 13125 Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20428112" target="_blank"〉PubMed〈/a〉
    Keywords: Antiviral Agents/chemistry/metabolism/pharmacology ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Dynamins/*chemistry/metabolism ; GTP Phosphohydrolases/metabolism ; GTP-Binding Proteins/*chemistry/genetics/*metabolism/pharmacology ; Guanosine Triphosphate/metabolism ; Humans ; Hydrolysis ; Hydrophobic and Hydrophilic Interactions ; Influenza A Virus, H5N1 Subtype/drug effects/physiology ; Models, Molecular ; Myxovirus Resistance Proteins ; Protein Conformation ; *Protein Multimerization ; Virus Replication/drug effects
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  • 27
    Publication Date: 2010-07-30
    Description: The post-translational methylation of alpha-amino groups was first discovered over 30 years ago on the bacterial ribosomal proteins L16 and L33 (refs 1, 2), but almost nothing is known about the function or enzymology of this modification. Several other bacterial and eukaryotic proteins have since been shown to be alpha-N-methylated. However, the Ran guanine nucleotide-exchange factor, RCC1, is the only protein for which any biological function of alpha-N-methylation has been identified. Methylation-defective mutants of RCC1 have reduced affinity for DNA and cause mitotic defects, but further characterization of this modification has been hindered by ignorance of the responsible methyltransferase. All fungal and animal N-terminally methylated proteins contain a unique N-terminal motif, Met-(Ala/Pro/Ser)-Pro-Lys, indicating that they may be targets of the same, unknown enzyme. The initiating Met is cleaved, and the exposed alpha-amino group is mono-, di- or trimethylated. Here we report the discovery of the first alpha-N-methyltransferase, which we named N-terminal RCC1 methyltransferase (NRMT). Substrate docking and mutational analysis of RCC1 defined the NRMT recognition sequence and enabled the identification of numerous new methylation targets, including SET (also known as TAF-I or PHAPII) and the retinoblastoma protein, RB. Knockdown of NRMT recapitulates the multi-spindle phenotype seen with methylation-defective RCC1 mutants, demonstrating the importance of alpha-N-methylation for normal bipolar spindle formation and chromosome segregation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939154/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939154/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tooley, Christine E Schaner -- Petkowski, Janusz J -- Muratore-Schroeder, Tara L -- Balsbaugh, Jeremy L -- Shabanowitz, Jeffrey -- Sabat, Michal -- Minor, Wladek -- Hunt, Donald F -- Macara, Ian G -- R01 GM050526/GM/NIGMS NIH HHS/ -- R01 GM050526-17/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Aug 26;466(7310):1125-8. doi: 10.1038/nature09343.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA. ces5g@virginia.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20668449" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Cycle Proteins/*metabolism ; Cell Line ; Chromosome Segregation ; Gene Knockdown Techniques ; Guanine Nucleotide Exchange Factors/*metabolism ; HeLa Cells ; Histone Chaperones/metabolism ; Humans ; Methyltransferases/chemistry/genetics/*metabolism ; Models, Molecular ; Mutation/genetics ; Nuclear Proteins/*metabolism ; Protein Binding ; Protein Structure, Tertiary ; Retinoblastoma Protein/*metabolism ; Spindle Apparatus/metabolism ; Transcription Factors/metabolism
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  • 28
    Publication Date: 2010-01-16
    Description: Phytochromes are a collection of bilin-containing photoreceptors that regulate numerous photoresponses in plants and microorganisms through their ability to photointerconvert between a red-light-absorbing, ground state (Pr) and a far-red-light-absorbing, photoactivated state (Pfr). Although the structures of several phytochromes as Pr have been determined, little is known about the structure of Pfr and how it initiates signalling. Here we describe the three-dimensional solution structure of the bilin-binding domain as Pfr, using the cyanobacterial phytochrome from Synechococcus OSB'. Contrary to predictions, light-induced rotation of the A pyrrole ring but not the D ring is the primary motion of the chromophore during photoconversion. Subsequent rearrangements within the protein then affect intradomain and interdomain contact sites within the phytochrome dimer. On the basis of our models, we propose that phytochromes act by propagating reversible light-driven conformational changes in the bilin to altered contacts between the adjacent output domains, which in most phytochromes direct differential phosphotransfer.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2807988/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2807988/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ulijasz, Andrew T -- Cornilescu, Gabriel -- Cornilescu, Claudia C -- Zhang, Junrui -- Rivera, Mario -- Markley, John L -- Vierstra, Richard D -- P41 RR002301/RR/NCRR NIH HHS/ -- P41 RR002301-237748/RR/NCRR NIH HHS/ -- U54 GM074901/GM/NIGMS NIH HHS/ -- U54 GM074901-05/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jan 14;463(7278):250-4. doi: 10.1038/nature08671.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics and, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20075921" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids/chemistry/metabolism/radiation effects ; Bacterial Proteins/*chemistry/genetics/metabolism/*radiation effects ; Bile Pigments/chemistry/metabolism/radiation effects ; Binding Sites ; *Light ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Phytochrome/*chemistry/genetics/metabolism/*radiation effects ; Protein Kinases/*chemistry/genetics/metabolism/*radiation effects ; Protein Structure, Tertiary/radiation effects ; Rotation ; Synechococcus/*chemistry/genetics
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  • 29
    Publication Date: 2010-08-20
    Description: The Na(+)/K(+)-ATPase pumps three sodium ions out of and two potassium ions into the cell for each ATP molecule that is split, thereby generating the chemical and electrical gradients across the plasma membrane that are essential in, for example, signalling, secondary transport and volume regulation in animal cells. Crystal structures of the potassium-bound form of the pump revealed an intimate docking of the alpha-subunit carboxy terminus at the transmembrane domain. Here we show that this element is a key regulator of a previously unrecognized ion pathway. Current models of P-type ATPases operate with a single ion conduit through the pump, but our data suggest an additional pathway in the Na(+)/K(+)-ATPase between the ion-binding sites and the cytoplasm. The C-terminal pathway allows a cytoplasmic proton to enter and stabilize site III when empty in the potassium-bound state, and when potassium is released the proton will also return to the cytoplasm, thus allowing an overall asymmetric stoichiometry of the transported ions. The C terminus controls the gate to the pathway. Its structure is crucial for pump function, as demonstrated by at least eight mutations in the region that cause severe neurological diseases. This novel model for ion transport by the Na(+)/K(+)-ATPase is established by electrophysiological studies of C-terminal mutations in familial hemiplegic migraine 2 (FHM2) and is further substantiated by molecular dynamics simulations. A similar ion regulation is likely to apply to the H(+)/K(+)-ATPase and the Ca(2+)-ATPase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Poulsen, Hanne -- Khandelia, Himanshu -- Morth, J Preben -- Bublitz, Maike -- Mouritsen, Ole G -- Egebjerg, Jan -- Nissen, Poul -- England -- Nature. 2010 Sep 2;467(7311):99-102. doi: 10.1038/nature09309. Epub 2010 Aug 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉PUMPKIN - Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology, Aarhus University, DK-8000 Aarhus C, Denmark. hp@mb.au.dk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20720542" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Crystallography, X-Ray ; Humans ; *Ion Transport ; Migraine with Aura/genetics/*metabolism ; Models, Molecular ; Molecular Dynamics Simulation ; Oocytes/metabolism ; Potassium/metabolism ; Protons ; Sodium-Potassium-Exchanging ATPase/*chemistry/*metabolism ; Squalus acanthias/metabolism ; Sus scrofa/metabolism ; Xenopus
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  • 30
    Publication Date: 2010-04-09
    Description: X-ray diffraction plays a pivotal role in the understanding of biological systems by revealing atomic structures of proteins, nucleic acids and their complexes, with much recent interest in very large assemblies like the ribosome. As crystals of such large assemblies often diffract weakly (resolution worse than 4 A), we need methods that work at such low resolution. In macromolecular assemblies, some of the components may be known at high resolution, whereas others are unknown: current refinement methods fail as they require a high-resolution starting structure for the entire complex. Determining the structure of such complexes, which are often of key biological importance, should be possible in principle as the number of independent diffraction intensities at a resolution better than 5 A generally exceeds the number of degrees of freedom. Here we introduce a method that adds specific information from known homologous structures but allows global and local deformations of these homology models. Our approach uses the observation that local protein structure tends to be conserved as sequence and function evolve. Cross-validation with R(free) (the free R-factor) determines the optimum deformation and influence of the homology model. For test cases at 3.5-5 A resolution with known structures at high resolution, our method gives significant improvements over conventional refinement in the model as monitored by coordinate accuracy, the definition of secondary structure and the quality of electron density maps. For re-refinements of a representative set of 19 low-resolution crystal structures from the Protein Data Bank, we find similar improvements. Thus, a structure derived from low-resolution diffraction data can have quality similar to a high-resolution structure. Our method is applicable to the study of weakly diffracting crystals using X-ray micro-diffraction as well as data from new X-ray light sources. Use of homology information is not restricted to X-ray crystallography and cryo-electron microscopy: as optical imaging advances to subnanometre resolution, it can use similar tools.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859093/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859093/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schroder, Gunnar F -- Levitt, Michael -- Brunger, Axel T -- EY016525/EY/NEI NIH HHS/ -- GM63718/GM/NIGMS NIH HHS/ -- R01 GM063817/GM/NIGMS NIH HHS/ -- U54 GM072970/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Apr 22;464(7292):1218-22. doi: 10.1038/nature08892. Epub 2010 Apr 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Strukturbiologie und Biophysik (ISB-3), Forschungszentrum Julich, 52425 Julich, Germany. gu.schroeder@fz-juelich.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20376006" target="_blank"〉PubMed〈/a〉
    Keywords: Crystallization ; Crystallography, X-Ray/*methods ; Databases, Protein ; Electrons ; Likelihood Functions ; Models, Molecular ; Oligopeptides/chemistry ; Protein Conformation ; Software ; Static Electricity
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  • 31
    Publication Date: 2010-02-05
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bhattacharya, Ananyo -- England -- Nature. 2010 Feb 4;463(7281):605-6. doi: 10.1038/463605a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20130626" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Child ; Crystallization ; Crystallography, X-Ray ; Diacylglycerol Kinase/chemistry ; Humans ; Magnetic Resonance Spectroscopy/*instrumentation/*methods ; Metabolomics/instrumentation/methods ; Models, Molecular ; Protein Conformation
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  • 32
    Publication Date: 2010-05-14
    Description: A huge variety of proteins are able to form fibrillar structures, especially at high protein concentrations. Hence, it is surprising that spider silk proteins can be stored in a soluble form at high concentrations and transformed into extremely stable fibres on demand. Silk proteins are reminiscent of amphiphilic block copolymers containing stretches of polyalanine and glycine-rich polar elements forming a repetitive core flanked by highly conserved non-repetitive amino-terminal and carboxy-terminal domains. The N-terminal domain comprises a secretion signal, but further functions remain unassigned. The C-terminal domain was implicated in the control of solubility and fibre formation initiated by changes in ionic composition and mechanical stimuli known to align the repetitive sequence elements and promote beta-sheet formation. However, despite recent structural data, little is known about this remarkable behaviour in molecular detail. Here we present the solution structure of the C-terminal domain of a spider dragline silk protein and provide evidence that the structural state of this domain is essential for controlled switching between the storage and assembly forms of silk proteins. In addition, the C-terminal domain also has a role in the alignment of secondary structural features formed by the repetitive elements in the backbone of spider silk proteins, which is known to be important for the mechanical properties of the fibre.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hagn, Franz -- Eisoldt, Lukas -- Hardy, John G -- Vendrely, Charlotte -- Coles, Murray -- Scheibel, Thomas -- Kessler, Horst -- England -- Nature. 2010 May 13;465(7295):239-42. doi: 10.1038/nature08936.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Integrated Protein Science (CIPSM), Technische Universitat Munchen, 85747 Garching, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463741" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calorimetry, Differential Scanning ; Circular Dichroism ; *Conserved Sequence ; Hydrophobic and Hydrophilic Interactions ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Protein Structure, Tertiary ; Silk/*chemistry/*metabolism ; Spectrometry, Fluorescence ; Spectroscopy, Fourier Transform Infrared ; Spiders/*chemistry
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  • 33
    Publication Date: 2010-01-15
    Description: Immune homeostasis is dependent on tight control over the size of a population of regulatory T (T(reg)) cells capable of suppressing over-exuberant immune responses. The T(reg) cell subset is comprised of cells that commit to the T(reg) lineage by upregulating the transcription factor Foxp3 either in the thymus (tT(reg)) or in the periphery (iT(reg)). Considering a central role for Foxp3 in T(reg) cell differentiation and function, we proposed that conserved non-coding DNA sequence (CNS) elements at the Foxp3 locus encode information defining the size, composition and stability of the T(reg) cell population. Here we describe the function of three Foxp3 CNS elements (CNS1-3) in T(reg) cell fate determination in mice. The pioneer element CNS3, which acts to potently increase the frequency of T(reg) cells generated in the thymus and the periphery, binds c-Rel in in vitro assays. In contrast, CNS1, which contains a TGF-beta-NFAT response element, is superfluous for tT(reg) cell differentiation, but has a prominent role in iT(reg) cell generation in gut-associated lymphoid tissues. CNS2, although dispensable for Foxp3 induction, is required for Foxp3 expression in the progeny of dividing T(reg) cells. Foxp3 binds to CNS2 in a Cbf-beta-Runx1 and CpG DNA demethylation-dependent manner, suggesting that Foxp3 recruitment to this 'cellular memory module' facilitates the heritable maintenance of the active state of the Foxp3 locus and, therefore, T(reg) lineage stability. Together, our studies demonstrate that the composition, size and maintenance of the T(reg) cell population are controlled by Foxp3 CNS elements engaged in response to distinct cell-extrinsic or -intrinsic cues.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884187/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884187/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zheng, Ye -- Josefowicz, Steven -- Chaudhry, Ashutosh -- Peng, Xiao P -- Forbush, Katherine -- Rudensky, Alexander Y -- R37 AI034206/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Feb 11;463(7282):808-12. doi: 10.1038/nature08750. Epub 2010 Jan 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Department of Immunology, University of Washington, Seattle, Washington 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20072126" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Differentiation ; Cell Lineage/*genetics ; Chromatin Assembly and Disassembly ; Conserved Sequence/*genetics ; CpG Islands/genetics ; DNA Methylation ; Female ; Forkhead Transcription Factors/*genetics/metabolism ; Gene Expression Regulation ; Lymphocyte Count ; Male ; Mice ; Mice, Inbred C57BL ; Proto-Oncogene Proteins c-rel/metabolism ; Regulatory Sequences, Nucleic Acid/*genetics ; Response Elements/genetics ; T-Lymphocytes, Regulatory/*cytology/immunology/*metabolism ; Thymus Gland/cytology/immunology/metabolism
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  • 34
    Publication Date: 2010-11-12
    Description: The central amygdala (CEA), a nucleus predominantly composed of GABAergic inhibitory neurons, is essential for fear conditioning. How the acquisition and expression of conditioned fear are encoded within CEA inhibitory circuits is not understood. Using in vivo electrophysiological, optogenetic and pharmacological approaches in mice, we show that neuronal activity in the lateral subdivision of the central amygdala (CEl) is required for fear acquisition, whereas conditioned fear responses are driven by output neurons in the medial subdivision (CEm). Functional circuit analysis revealed that inhibitory CEA microcircuits are highly organized and that cell-type-specific plasticity of phasic and tonic activity in the CEl to CEm pathway may gate fear expression and regulate fear generalization. Our results define the functional architecture of CEA microcircuits and their role in the acquisition and regulation of conditioned fear behaviour.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ciocchi, Stephane -- Herry, Cyril -- Grenier, Francois -- Wolff, Steffen B E -- Letzkus, Johannes J -- Vlachos, Ioannis -- Ehrlich, Ingrid -- Sprengel, Rolf -- Deisseroth, Karl -- Stadler, Michael B -- Muller, Christian -- Luthi, Andreas -- England -- Nature. 2010 Nov 11;468(7321):277-82. doi: 10.1038/nature09559.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21068837" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Amygdala/anatomy & histology/cytology/*physiology ; Animals ; Conditioning, Classical/*physiology ; Fear/*physiology ; Freezing Reaction, Cataleptic ; Male ; Mice ; Mice, Inbred C57BL ; Neural Inhibition/*physiology ; Neural Pathways/cytology/*physiology ; Neuronal Plasticity/physiology ; Neurons/physiology ; gamma-Aminobutyric Acid/metabolism
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  • 35
    Publication Date: 2010-12-24
    Description: The multi-component mechanistic target of rapamycin complex 1 (mTORC1) kinase is the central node of a mammalian pathway that coordinates cell growth with the availability of nutrients, energy and growth factors. Progress has been made in the identification of mTORC1 pathway components and in understanding their functions in cells, but there is relatively little known about the role of the pathway in vivo. Specifically, we have little knowledge regarding the role mTOCR1 has in liver physiology. In fasted animals, the liver performs numerous functions that maintain whole-body homeostasis, including the production of ketone bodies for peripheral tissues to use as energy sources. Here we show that mTORC1 controls ketogenesis in mice in response to fasting. We find that liver-specific loss of TSC1 (tuberous sclerosis 1), an mTORC1 inhibitor, leads to a fasting-resistant increase in liver size, and to a pronounced defect in ketone body production and ketogenic gene expression on fasting. The loss of raptor (regulatory associated protein of mTOR, complex 1) an essential mTORC1 component, has the opposite effects. In addition, we find that the inhibition of mTORC1 is required for the fasting-induced activation of PPARalpha (peroxisome proliferator activated receptor alpha), the master transcriptional activator of ketogenic genes, and that suppression of NCoR1 (nuclear receptor co-repressor 1), a co-repressor of PPARalpha, reactivates ketogenesis in cells and livers with hyperactive mTORC1 signalling. Like livers with activated mTORC1, livers from aged mice have a defect in ketogenesis, which correlates with an increase in mTORC1 signalling. Moreover, we show that the suppressive effects of mTORC1 activation and ageing on PPARalpha activity and ketone production are not additive, and that mTORC1 inhibition is sufficient to prevent the ageing-induced defect in ketogenesis. Thus, our findings reveal that mTORC1 is a key regulator of PPARalpha function and hepatic ketogenesis and suggest a role for mTORC1 activity in promoting the ageing of the liver.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sengupta, Shomit -- Peterson, Timothy R -- Laplante, Mathieu -- Oh, Stephanie -- Sabatini, David M -- CA103866/CA/NCI NIH HHS/ -- CA129105/CA/NCI NIH HHS/ -- R01 CA129105/CA/NCI NIH HHS/ -- R01 CA129105-04/CA/NCI NIH HHS/ -- Canadian Institutes of Health Research/Canada -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Dec 23;468(7327):1100-4. doi: 10.1038/nature09584.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, Massachusetts 02142, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21179166" target="_blank"〉PubMed〈/a〉
    Keywords: *Aging ; Animals ; Cell Line ; Fasting/*metabolism ; *Gene Expression Regulation ; Humans ; Ketone Bodies/*biosynthesis/metabolism ; Liver/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Multiprotein Complexes ; Nuclear Receptor Co-Repressor 1/metabolism ; PPAR alpha/antagonists & inhibitors/metabolism ; Proteins/genetics/*metabolism ; TOR Serine-Threonine Kinases
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  • 36
    Publication Date: 2010-11-05
    Description: Stroke is a leading cause of disability, but no pharmacological therapy is currently available for promoting recovery. The brain region adjacent to stroke damage-the peri-infarct zone-is critical for rehabilitation, as it shows heightened neuroplasticity, allowing sensorimotor functions to re-map from damaged areas. Thus, understanding the neuronal properties constraining this plasticity is important for the development of new treatments. Here we show that after a stroke in mice, tonic neuronal inhibition is increased in the peri-infarct zone. This increased tonic inhibition is mediated by extrasynaptic GABA(A) receptors and is caused by an impairment in GABA (gamma-aminobutyric acid) transporter (GAT-3/GAT-4) function. To counteract the heightened inhibition, we administered in vivo a benzodiazepine inverse agonist specific for alpha5-subunit-containing extrasynaptic GABA(A) receptors at a delay after stroke. This treatment produced an early and sustained recovery of motor function. Genetically lowering the number of alpha5- or delta-subunit-containing GABA(A) receptors responsible for tonic inhibition also proved beneficial for recovery after stroke, consistent with the therapeutic potential of diminishing extrasynaptic GABA(A) receptor function. Together, our results identify new pharmacological targets and provide the rationale for a novel strategy to promote recovery after stroke and possibly other brain injuries.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058798/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058798/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clarkson, Andrew N -- Huang, Ben S -- Macisaac, Sarah E -- Mody, Istvan -- Carmichael, S Thomas -- NS30549/NS/NINDS NIH HHS/ -- R01 NS030549/NS/NINDS NIH HHS/ -- R01 NS030549-18/NS/NINDS NIH HHS/ -- England -- Nature. 2010 Nov 11;468(7321):305-9. doi: 10.1038/nature09511. Epub 2010 Nov 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurology, The David Geffen School of Medicine at UCLA, 635 Charles Young Drive South, Los Angeles, California 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21048709" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Benzodiazepines/pharmacology ; Cerebral Infarction/metabolism/pathology/physiopathology ; Disease Models, Animal ; Drug Inverse Agonism ; GABA Antagonists/pharmacology ; GABA Plasma Membrane Transport Proteins/metabolism ; Imidazoles/pharmacology ; Male ; Membrane Potentials/drug effects ; Mice ; Mice, Inbred C57BL ; Motor Cortex/metabolism/pathology/*physiology/*physiopathology ; Neuronal Plasticity/physiology ; Receptors, GABA/deficiency/genetics/metabolism ; Recovery of Function/*physiology ; Stroke/drug therapy/*metabolism/pathology ; Synapses/metabolism ; Time Factors ; gamma-Aminobutyric Acid/*metabolism
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  • 37
    Publication Date: 2010-01-08
    Description: G-protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters. They are the largest group of therapeutic targets for a broad spectrum of diseases. Recent crystal structures of GPCRs have revealed structural conservation extending from the orthosteric ligand-binding site in the transmembrane core to the cytoplasmic G-protein-coupling domains. In contrast, the extracellular surface (ECS) of GPCRs is remarkably diverse and is therefore an ideal target for the discovery of subtype-selective drugs. However, little is known about the functional role of the ECS in receptor activation, or about conformational coupling of this surface to the native ligand-binding pocket. Here we use NMR spectroscopy to investigate ligand-specific conformational changes around a central structural feature in the ECS of the beta(2) adrenergic receptor: a salt bridge linking extracellular loops 2 and 3. Small-molecule drugs that bind within the transmembrane core and exhibit different efficacies towards G-protein activation (agonist, neutral antagonist and inverse agonist) also stabilize distinct conformations of the ECS. We thereby demonstrate conformational coupling between the ECS and the orthosteric binding site, showing that drugs targeting this diverse surface could function as allosteric modulators with high subtype selectivity. Moreover, these studies provide a new insight into the dynamic behaviour of GPCRs not addressable by static, inactive-state crystal structures.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805469/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805469/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bokoch, Michael P -- Zou, Yaozhong -- Rasmussen, Soren G F -- Liu, Corey W -- Nygaard, Rie -- Rosenbaum, Daniel M -- Fung, Juan Jose -- Choi, Hee-Jung -- Thian, Foon Sun -- Kobilka, Tong Sun -- Puglisi, Joseph D -- Weis, William I -- Pardo, Leonardo -- Prosser, R Scott -- Mueller, Luciano -- Kobilka, Brian K -- GM56169/GM/NIGMS NIH HHS/ -- NS028471/NS/NINDS NIH HHS/ -- R01 GM056169/GM/NIGMS NIH HHS/ -- R01 GM056169-13/GM/NIGMS NIH HHS/ -- R21 MH082313/MH/NIMH NIH HHS/ -- R21 MH082313-01A1/MH/NIMH NIH HHS/ -- R37 NS028471/NS/NINDS NIH HHS/ -- R37 NS028471-19/NS/NINDS NIH HHS/ -- England -- Nature. 2010 Jan 7;463(7277):108-12. doi: 10.1038/nature08650.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20054398" target="_blank"〉PubMed〈/a〉
    Keywords: Adrenergic beta-2 Receptor Agonists ; Adrenergic beta-2 Receptor Antagonists ; Allosteric Regulation/drug effects ; Binding Sites ; Crystallography, X-Ray ; Drug Inverse Agonism ; Ethanolamines/pharmacology ; Formoterol Fumarate ; Humans ; Ligands ; Lysine/analogs & derivatives/metabolism ; Methylation ; Models, Molecular ; Mutant Proteins ; Nuclear Magnetic Resonance, Biomolecular ; Propanolamines/metabolism/pharmacology ; Protein Structure, Tertiary/drug effects ; Receptors, Adrenergic, beta-2/*chemistry/*metabolism ; Static Electricity ; Substrate Specificity
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  • 38
    Publication Date: 2010-08-13
    Description: Increased levels of brain amyloid-beta, a secreted peptide cleavage product of amyloid precursor protein (APP), is believed to be critical in the aetiology of Alzheimer's disease. Increased amyloid-beta can cause synaptic depression, reduce the number of spine protrusions (that is, sites of synaptic contacts) and block long-term synaptic potentiation (LTP), a form of synaptic plasticity; however, the receptor through which amyloid-beta produces these synaptic perturbations has remained elusive. Lauren et al. suggested that binding between oligomeric amyloid-beta (a form of amyloid-beta thought to be most active) and the cellular prion protein (PrP(C)) is necessary for synaptic perturbations. Here we show that PrP(C) is not required for amyloid-beta-induced synaptic depression, reduction in spine density, or blockade of LTP; our results indicate that amyloid-beta-mediated synaptic defects do not require PrP(c).〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057871/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057871/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kessels, Helmut W -- Nguyen, Louis N -- Nabavi, Sadegh -- Malinow, Roberto -- R01 AG032132/AG/NIA NIH HHS/ -- R01 AG032132-14/AG/NIA NIH HHS/ -- R01 AG032132-15/AG/NIA NIH HHS/ -- R01 AG032132-17/AG/NIA NIH HHS/ -- R01 AG032132-18/AG/NIA NIH HHS/ -- R01 MH049159/MH/NIMH NIH HHS/ -- R01 MH049159-09/MH/NIMH NIH HHS/ -- R01 MH049159-21/MH/NIMH NIH HHS/ -- R01 MH049159-22/MH/NIMH NIH HHS/ -- England -- Nature. 2010 Aug 12;466(7308):E3-4; discussion E4-5. doi: 10.1038/nature09217.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Neural Circuits and Behavior, 9500 Gilman Drive 0634, University of California at San Diego, La Jolla, California 92093, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20703260" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/metabolism/pathology ; Amyloid beta-Peptides/chemistry/genetics/*metabolism ; Animals ; Learning/physiology ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; PrPC Proteins/deficiency/genetics/*metabolism ; Reproducibility of Results ; Serotonin/metabolism ; Synapses/*metabolism/*pathology ; Synaptic Transmission
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  • 39
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    Nature Publishing Group (NPG)
    Publication Date: 2010-05-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Katsnelson, Alla -- England -- Nature. 2010 May 13;465(7295):145. doi: 10.1038/465145a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463710" target="_blank"〉PubMed〈/a〉
    Keywords: *DNA Methylation ; Epigenesis, Genetic/*genetics ; Genome, Human/genetics ; Genomics/*methods ; Humans ; Models, Molecular ; Neoplasms/genetics ; Sequence Analysis, DNA/*methods
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  • 40
    Publication Date: 2010-08-06
    Description: People exert large amounts of problem-solving effort playing computer games. Simple image- and text-recognition tasks have been successfully 'crowd-sourced' through games, but it is not clear if more complex scientific problems can be solved with human-directed computing. Protein structure prediction is one such problem: locating the biologically relevant native conformation of a protein is a formidable computational challenge given the very large size of the search space. Here we describe Foldit, a multiplayer online game that engages non-scientists in solving hard prediction problems. Foldit players interact with protein structures using direct manipulation tools and user-friendly versions of algorithms from the Rosetta structure prediction methodology, while they compete and collaborate to optimize the computed energy. We show that top-ranked Foldit players excel at solving challenging structure refinement problems in which substantial backbone rearrangements are necessary to achieve the burial of hydrophobic residues. Players working collaboratively develop a rich assortment of new strategies and algorithms; unlike computational approaches, they explore not only the conformational space but also the space of possible search strategies. The integration of human visual problem-solving and strategy development capabilities with traditional computational algorithms through interactive multiplayer games is a powerful new approach to solving computationally-limited scientific problems.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956414/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956414/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cooper, Seth -- Khatib, Firas -- Treuille, Adrien -- Barbero, Janos -- Lee, Jeehyung -- Beenen, Michael -- Leaver-Fay, Andrew -- Baker, David -- Popovic, Zoran -- Players, Foldit -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Aug 5;466(7307):756-60. doi: 10.1038/nature09304.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Computer Science and Engineering, University of Washington, Box 352350, Seattle, Washington 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20686574" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Computational Biology/*methods ; Computer Graphics ; Computer Simulation ; Cooperative Behavior ; Cues ; *Games, Experimental ; *Group Processes ; Humans ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Imaging, Three-Dimensional ; *Internet ; Leisure Activities ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Photic Stimulation ; *Problem Solving ; Protein Conformation ; *Protein Folding ; Proteins/*chemistry/metabolism ; Stochastic Processes ; Thermodynamics
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  • 41
    Publication Date: 2010-09-17
    Description: Specialized cellular microenvironments, or 'niches', modulate stem cell properties, including cell number, self-renewal and fate decisions. In the adult brain, niches that maintain a source of neural stem cells (NSCs) and neural progenitor cells (NPCs) are the subventricular zone (SVZ) of the lateral ventricle and the dentate gyrus of the hippocampus. The size of the NSC population of the SVZ at any time is the result of several ongoing processes, including self-renewal, cell differentiation, and cell death. Maintaining the balance between NSCs and NPCs in the SVZ niche is critical to supply the brain with specific neural populations, both under normal conditions or after injury. A fundamental question relevant to both normal development and to cell-based repair strategies in the central nervous system is how the balance of different NSC and NPC populations is maintained in the niche. EGFR (epidermal growth factor receptor) and Notch signalling pathways have fundamental roles during development of multicellular organisms. In Drosophila and in Caenorhabditis elegans these pathways may have either cooperative or antagonistic functions. In the SVZ, Notch regulates NSC identity and self-renewal, whereas EGFR specifically affects NPC proliferation and migration. This suggests that interplay of these two pathways may maintain the balance between NSC and NPC numbers. Here we show that functional cell-cell interaction between NPCs and NSCs through EGFR and Notch signalling has a crucial role in maintaining the balance between these cell populations in the SVZ. Enhanced EGFR signalling in vivo results in the expansion of the NPC pool, and reduces NSC number and self-renewal. This occurs through a non-cell-autonomous mechanism involving EGFR-mediated regulation of Notch signalling. Our findings define a novel interaction between EGFR and Notch pathways in the adult SVZ, and thus provide a mechanism for NSC and NPC pool maintenance.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2941915/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2941915/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Aguirre, Adan -- Rubio, Maria E -- Gallo, Vittorio -- K99NS057944/NS/NINDS NIH HHS/ -- P30HD40677/HD/NICHD NIH HHS/ -- R00 NS057944/NS/NINDS NIH HHS/ -- R01 DC006881/DC/NIDCD NIH HHS/ -- R01 DC006881-03/DC/NIDCD NIH HHS/ -- R01 DC006881-04/DC/NIDCD NIH HHS/ -- R01DC006881/DC/NIDCD NIH HHS/ -- R01NS045702/NS/NINDS NIH HHS/ -- R01NS056427/NS/NINDS NIH HHS/ -- R0O NS057944-03/NS/NINDS NIH HHS/ -- England -- Nature. 2010 Sep 16;467(7313):323-7. doi: 10.1038/nature09347.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Neuroscience Research, Children's National Medical Center, Washington, District of Columbia 20010, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20844536" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Count ; Cell Division ; Humans ; Membrane Proteins/deficiency/genetics/metabolism ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins/deficiency/genetics/metabolism ; Neurons/*cytology ; Protein Binding ; Receptor, Epidermal Growth Factor/genetics/*metabolism ; Receptor, Notch1/metabolism ; Receptors, Notch/*metabolism ; *Signal Transduction ; Stem Cell Niche/cytology ; Stem Cells/*cytology ; Ubiquitination
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  • 42
    Publication Date: 2010-09-24
    Description: Symplekin (Pta1 in yeast) is a scaffold in the large protein complex that is required for 3'-end cleavage and polyadenylation of eukaryotic messenger RNA precursors (pre-mRNAs); it also participates in transcription initiation and termination by RNA polymerase II (Pol II). Symplekin mediates interactions between many different proteins in this machinery, although the molecular basis for its function is not known. Here we report the crystal structure at 2.4 A resolution of the amino-terminal domain (residues 30-340) of human symplekin in a ternary complex with the Pol II carboxy-terminal domain (CTD) Ser 5 phosphatase Ssu72 (refs 7, 10-17) and a CTD Ser 5 phosphopeptide. The N-terminal domain of symplekin has the ARM or HEAT fold, with seven pairs of antiparallel alpha-helices arranged in the shape of an arc. The structure of Ssu72 has some similarity to that of low-molecular-mass phosphotyrosine protein phosphatase, although Ssu72 has a unique active-site landscape as well as extra structural features at the C terminus that are important for interaction with symplekin. Ssu72 is bound to the concave face of symplekin, and engineered mutations in this interface can abolish interactions between the two proteins. The CTD peptide is bound in the active site of Ssu72, with the pSer 5-Pro 6 peptide bond in the cis configuration, which contrasts with all other known CTD peptide conformations. Although the active site of Ssu72 is about 25 A from the interface with symplekin, we found that the symplekin N-terminal domain stimulates Ssu72 CTD phosphatase activity in vitro. Furthermore, the N-terminal domain of symplekin inhibits polyadenylation in vitro, but only when coupled to transcription. Because catalytically active Ssu72 overcomes this inhibition, our results show a role for mammalian Ssu72 in transcription-coupled pre-mRNA 3'-end processing.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038789/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038789/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xiang, Kehui -- Nagaike, Takashi -- Xiang, Song -- Kilic, Turgay -- Beh, Maia M -- Manley, James L -- Tong, Liang -- GM028983/GM/NIGMS NIH HHS/ -- GM077175/GM/NIGMS NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 GM028983/GM/NIGMS NIH HHS/ -- R01 GM028983-31/GM/NIGMS NIH HHS/ -- R01 GM077175/GM/NIGMS NIH HHS/ -- R01 GM077175-04/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Oct 7;467(7316):729-33. doi: 10.1038/nature09391. Epub 2010 Sep 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Columbia University, New York, New York 10027, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20861839" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding Sites ; Carrier Proteins/*chemistry/genetics/*metabolism ; Catalytic Domain ; Crystallography, X-Ray ; Drosophila Proteins/chemistry ; Humans ; Models, Molecular ; Nuclear Proteins/*chemistry/genetics/*metabolism ; Phosphopeptides/chemistry/*metabolism ; Phosphoprotein Phosphatases/chemistry/genetics/metabolism ; Polyadenylation ; Protein Binding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; RNA Polymerase II/*chemistry/*metabolism ; Saccharomyces cerevisiae Proteins/chemistry ; Substrate Specificity ; mRNA Cleavage and Polyadenylation Factors/chemistry
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  • 43
    Publication Date: 2010-04-30
    Description: The inflammatory nature of atherosclerosis is well established but the agent(s) that incite inflammation in the artery wall remain largely unknown. Germ-free animals are susceptible to atherosclerosis, suggesting that endogenous substances initiate the inflammation. Mature atherosclerotic lesions contain macroscopic deposits of cholesterol crystals in the necrotic core, but their appearance late in atherogenesis had been thought to disqualify them as primary inflammatory stimuli. However, using a new microscopic technique, we revealed that minute cholesterol crystals are present in early diet-induced atherosclerotic lesions and that their appearance in mice coincides with the first appearance of inflammatory cells. Other crystalline substances can induce inflammation by stimulating the caspase-1-activating NLRP3 (NALP3 or cryopyrin) inflammasome, which results in cleavage and secretion of interleukin (IL)-1 family cytokines. Here we show that cholesterol crystals activate the NLRP3 inflammasome in phagocytes in vitro in a process that involves phagolysosomal damage. Similarly, when injected intraperitoneally, cholesterol crystals induce acute inflammation, which is impaired in mice deficient in components of the NLRP3 inflammasome, cathepsin B, cathepsin L or IL-1 molecules. Moreover, when mice deficient in low-density lipoprotein receptor (LDLR) were bone-marrow transplanted with NLRP3-deficient, ASC (also known as PYCARD)-deficient or IL-1alpha/beta-deficient bone marrow and fed on a high-cholesterol diet, they had markedly decreased early atherosclerosis and inflammasome-dependent IL-18 levels. Minimally modified LDL can lead to cholesterol crystallization concomitant with NLRP3 inflammasome priming and activation in macrophages. Although there is the possibility that oxidized LDL activates the NLRP3 inflammasome in vivo, our results demonstrate that crystalline cholesterol acts as an endogenous danger signal and its deposition in arteries or elsewhere is an early cause rather than a late consequence of inflammation. These findings provide new insights into the pathogenesis of atherosclerosis and indicate new potential molecular targets for the therapy of this disease.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946640/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946640/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Duewell, Peter -- Kono, Hajime -- Rayner, Katey J -- Sirois, Cherilyn M -- Vladimer, Gregory -- Bauernfeind, Franz G -- Abela, George S -- Franchi, Luigi -- Nunez, Gabriel -- Schnurr, Max -- Espevik, Terje -- Lien, Egil -- Fitzgerald, Katherine A -- Rock, Kenneth L -- Moore, Kathryn J -- Wright, Samuel D -- Hornung, Veit -- Latz, Eicke -- R01 AI075318/AI/NIAID NIH HHS/ -- R01 AI083713/AI/NIAID NIH HHS/ -- R01 AI083713-01/AI/NIAID NIH HHS/ -- R01 HL093262/HL/NHLBI NIH HHS/ -- R01 HL093262-01A1/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Apr 29;464(7293):1357-61. doi: 10.1038/nature08938.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20428172" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Apoptosis Regulatory Proteins ; Atherosclerosis/chemically induced/*metabolism/*pathology ; Bone Marrow Transplantation ; Carrier Proteins/genetics/*metabolism ; Cathepsin B/metabolism ; Cathepsin L/metabolism ; Cholesterol/*chemistry/*metabolism/pharmacology ; Crystallization ; Cytoskeletal Proteins/deficiency ; Diet, Atherogenic ; Female ; Humans ; Inflammation/chemically induced/metabolism/pathology ; Interleukin-1/deficiency ; Interleukin-18/metabolism ; Lysosomes/drug effects/pathology ; Mice ; Mice, Inbred C57BL ; Peritoneal Cavity/pathology ; Phagocytes/drug effects/pathology/physiology ; Receptors, LDL/deficiency ; Time Factors
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  • 44
    Publication Date: 2010-11-03
    Description: Natural killer cells and cytotoxic T lymphocytes accomplish the critically important function of killing virus-infected and neoplastic cells. They do this by releasing the pore-forming protein perforin and granzyme proteases from cytoplasmic granules into the cleft formed between the abutting killer and target cell membranes. Perforin, a 67-kilodalton multidomain protein, oligomerizes to form pores that deliver the pro-apoptopic granzymes into the cytosol of the target cell. The importance of perforin is highlighted by the fatal consequences of congenital perforin deficiency, with more than 50 different perforin mutations linked to familial haemophagocytic lymphohistiocytosis (type 2 FHL). Here we elucidate the mechanism of perforin pore formation by determining the X-ray crystal structure of monomeric murine perforin, together with a cryo-electron microscopy reconstruction of the entire perforin pore. Perforin is a thin 'key-shaped' molecule, comprising an amino-terminal membrane attack complex perforin-like (MACPF)/cholesterol dependent cytolysin (CDC) domain followed by an epidermal growth factor (EGF) domain that, together with the extreme carboxy-terminal sequence, forms a central shelf-like structure. A C-terminal C2 domain mediates initial, Ca(2+)-dependent membrane binding. Most unexpectedly, however, electron microscopy reveals that the orientation of the perforin MACPF domain in the pore is inside-out relative to the subunit arrangement in CDCs. These data reveal remarkable flexibility in the mechanism of action of the conserved MACPF/CDC fold and provide new insights into how related immune defence molecules such as complement proteins assemble into pores.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Law, Ruby H P -- Lukoyanova, Natalya -- Voskoboinik, Ilia -- Caradoc-Davies, Tom T -- Baran, Katherine -- Dunstone, Michelle A -- D'Angelo, Michael E -- Orlova, Elena V -- Coulibaly, Fasseli -- Verschoor, Sandra -- Browne, Kylie A -- Ciccone, Annette -- Kuiper, Michael J -- Bird, Phillip I -- Trapani, Joseph A -- Saibil, Helen R -- Whisstock, James C -- 079605/Wellcome Trust/United Kingdom -- BB/D008573/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- Arthritis Research UK/United Kingdom -- Biotechnology and Biological Sciences Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Nov 18;468(7322):447-51. doi: 10.1038/nature09518. Epub 2010 Oct 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Monash University, Clayton, Melbourne, Victoria 3800, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21037563" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Membrane/*metabolism ; Cholesterol/metabolism ; Cryoelectron Microscopy ; Crystallography, X-Ray ; Epidermal Growth Factor/chemistry ; Granzymes/metabolism ; Humans ; Lymphocytes/*metabolism ; Mice ; Models, Molecular ; Pore Forming Cytotoxic Proteins/*chemistry/genetics/*metabolism/ultrastructure ; Protein Structure, Tertiary
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  • 45
    Publication Date: 2010-10-22
    Description: Aberrant expression of microRNAs (miRNAs) and the enzymes that control their processing have been reported in multiple biological processes including primary and metastatic tumours, but the mechanisms governing this are not clearly understood. Here we show that TAp63, a p53 family member, suppresses tumorigenesis and metastasis, and coordinately regulates Dicer and miR-130b to suppress metastasis. Metastatic mouse and human tumours deficient in TAp63 express Dicer at very low levels, and we found that modulation of expression of Dicer and miR-130b markedly affected the metastatic potential of cells lacking TAp63. TAp63 binds to and transactivates the Dicer promoter, demonstrating direct transcriptional regulation of Dicer by TAp63. These data provide a novel understanding of the roles of TAp63 in tumour and metastasis suppression through the coordinate transcriptional regulation of Dicer and miR-130b and may have implications for the many processes regulated by miRNAs.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055799/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055799/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Su, Xiaohua -- Chakravarti, Deepavali -- Cho, Min Soon -- Liu, Lingzhi -- Gi, Young Jin -- Lin, Yu-Li -- Leung, Marco L -- El-Naggar, Adel -- Creighton, Chad J -- Suraokar, Milind B -- Wistuba, Ignacio -- Flores, Elsa R -- 01DE019765/DE/NIDCR NIH HHS/ -- CA16672/CA/NCI NIH HHS/ -- P30 CA016672-27/CA/NCI NIH HHS/ -- P50 CA070907/CA/NCI NIH HHS/ -- P50 CA070907-10/CA/NCI NIH HHS/ -- P50 CA091846/CA/NCI NIH HHS/ -- P50 CA091846-10/CA/NCI NIH HHS/ -- P50CA070907/CA/NCI NIH HHS/ -- P50CA091846/CA/NCI NIH HHS/ -- U01 DE019765/DE/NIDCR NIH HHS/ -- U01 DE019765-03/DE/NIDCR NIH HHS/ -- England -- Nature. 2010 Oct 21;467(7318):986-90. doi: 10.1038/nature09459.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20962848" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Aging ; Cell Line ; Cell Line, Tumor ; DEAD-box RNA Helicases/biosynthesis/deficiency/genetics/*metabolism ; Endoribonucleases/genetics/*metabolism ; Female ; *Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor/physiology ; Genomic Instability ; Humans ; Male ; Mice ; Mice, Inbred C57BL ; MicroRNAs/*biosynthesis/genetics/metabolism ; Neoplasm Metastasis/*genetics ; Neoplasms/genetics/pathology/secretion ; Phosphoproteins/deficiency/genetics/*metabolism ; Promoter Regions, Genetic/genetics ; Ribonuclease III/biosynthesis/deficiency/genetics/*metabolism ; Trans-Activators/deficiency/genetics/*metabolism ; Transcription Factors ; Transcriptional Activation ; Tumor Suppressor Proteins/deficiency/genetics/*metabolism
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  • 46
    Publication Date: 2010-09-24
    Description: Transporter proteins from the MATE (multidrug and toxic compound extrusion) family are vital in metabolite transport in plants, directly affecting crop yields worldwide. MATE transporters also mediate multiple-drug resistance (MDR) in bacteria and mammals, modulating the efficacy of many pharmaceutical drugs used in the treatment of a variety of diseases. MATE transporters couple substrate transport to electrochemical gradients and are the only remaining class of MDR transporters whose structure has not been determined. Here we report the X-ray structure of the MATE transporter NorM from Vibrio cholerae determined to 3.65 A, revealing an outward-facing conformation with two portals open to the outer leaflet of the membrane and a unique topology of the predicted 12 transmembrane helices distinct from any other known MDR transporter. We also report a cation-binding site in close proximity to residues previously deemed critical for transport. This conformation probably represents a stage of the transport cycle with high affinity for monovalent cations and low affinity for substrates.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152480/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152480/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉He, Xiao -- Szewczyk, Paul -- Karyakin, Andrey -- Evin, Mariah -- Hong, Wen-Xu -- Zhang, Qinghai -- Chang, Geoffrey -- GM70480/GM/NIGMS NIH HHS/ -- GM73197/GM/NIGMS NIH HHS/ -- P50 GM073197/GM/NIGMS NIH HHS/ -- P50 GM073197-07/GM/NIGMS NIH HHS/ -- R01 GM070480/GM/NIGMS NIH HHS/ -- R01 GM070480-01A1/GM/NIGMS NIH HHS/ -- R01 GM070480-02/GM/NIGMS NIH HHS/ -- R01 GM070480-03/GM/NIGMS NIH HHS/ -- R01 GM070480-04/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Oct 21;467(7318):991-4. doi: 10.1038/nature09408. Epub 2010 Sep 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, CB105, La Jolla, California 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20861838" target="_blank"〉PubMed〈/a〉
    Keywords: Antiporters/*chemistry/genetics/*metabolism ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Binding Sites ; Cations/chemistry/metabolism ; Crystallography, X-Ray ; Cysteine/genetics/metabolism ; Ion Transport ; Models, Molecular ; Protein Conformation ; Reproducibility of Results ; Static Electricity ; Substrate Specificity ; Vibrio cholerae/*chemistry
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  • 47
    Publication Date: 2010-02-05
    Description: Chronic myeloid leukaemia (CML) is caused by a defined genetic abnormality that generates BCR-ABL, a constitutively active tyrosine kinase. It is widely believed that BCR-ABL activates Akt signalling that suppresses the forkhead O transcription factors (FOXO), supporting the proliferation or inhibiting the apoptosis of CML cells. Although the use of the tyrosine kinase inhibitor imatinib is a breakthrough for CML therapy, imatinib does not deplete the leukaemia-initiating cells (LICs) that drive the recurrence of CML. Here, using a syngeneic transplantation system and a CML-like myeloproliferative disease mouse model, we show that Foxo3a has an essential role in the maintenance of CML LICs. We find that cells with nuclear localization of Foxo3a and decreased Akt phosphorylation are enriched in the LIC population. Serial transplantation of LICs generated from Foxo3a(+/+) and Foxo3a(-/-) mice shows that the ability of LICs to cause disease is significantly decreased by Foxo3a deficiency. Furthermore, we find that TGF-beta is a critical regulator of Akt activation in LICs and controls Foxo3a localization. A combination of TGF-beta inhibition, Foxo3a deficiency and imatinib treatment led to efficient depletion of CML in vivo. Furthermore, the treatment of human CML LICs with a TGF-beta inhibitor impaired their colony-forming ability in vitro. Our results demonstrate a critical role for the TGF-beta-FOXO pathway in the maintenance of LICs, and strengthen our understanding of the mechanisms that specifically maintain CML LICs in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Naka, Kazuhito -- Hoshii, Takayuki -- Muraguchi, Teruyuki -- Tadokoro, Yuko -- Ooshio, Takako -- Kondo, Yukio -- Nakao, Shinji -- Motoyama, Noboru -- Hirao, Atsushi -- England -- Nature. 2010 Feb 4;463(7281):676-80. doi: 10.1038/nature08734.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Molecular Genetics, Center for Cancer and Stem Cell Research, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa 920-0934, Japan. kazunaka@kenroku.kanazawa-u.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20130650" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antineoplastic Agents/therapeutic use ; Apoptosis ; Benzamides ; Cell Differentiation ; Cell Line, Tumor ; Cell Nucleus/metabolism ; Disease Models, Animal ; Enzyme Activation ; Forkhead Transcription Factors/deficiency/genetics/*metabolism ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug ; therapy/*metabolism/*pathology ; Mice ; Mice, Inbred C57BL ; Neoplastic Stem Cells/drug effects/*metabolism/*pathology ; Phosphorylation ; Piperazines/therapeutic use ; Protein Kinase Inhibitors/therapeutic use ; Protein Transport ; Protein-Tyrosine Kinases/antagonists & inhibitors ; Proto-Oncogene Proteins c-akt/metabolism ; Pyrimidines/therapeutic use ; *Signal Transduction/drug effects ; Transforming Growth Factor beta/antagonists & inhibitors/*metabolism ; Tumor Stem Cell Assay
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  • 48
    Publication Date: 2010-12-03
    Description: Little is known about metabolic regulation in stem cells and how this modulates tissue regeneration or tumour suppression. We studied the Lkb1 tumour suppressor and its substrate AMP-activated protein kinase (AMPK), kinases that coordinate metabolism with cell growth. Deletion of the Lkb1 (also called Stk11) gene in mice caused increased haematopoietic stem cell (HSC) division, rapid HSC depletion and pancytopenia. HSCs depended more acutely on Lkb1 for cell-cycle regulation and survival than many other haematopoietic cells. HSC depletion did not depend on mTOR activation or oxidative stress. Lkb1-deficient HSCs, but not myeloid progenitors, had reduced mitochondrial membrane potential and ATP levels. HSCs deficient for two catalytic alpha-subunits of AMPK (AMPK-deficient HSCs) showed similar changes in mitochondrial function but remained able to reconstitute irradiated mice. Lkb1-deficient HSCs, but not AMPK-deficient HSCs, exhibited defects in centrosomes and mitotic spindles in culture, and became aneuploid. Lkb1 is therefore required for HSC maintenance through AMPK-dependent and AMPK-independent mechanisms, revealing differences in metabolic and cell-cycle regulation between HSCs and some other haematopoietic progenitors.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059717/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059717/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nakada, Daisuke -- Saunders, Thomas L -- Morrison, Sean J -- CA46592/CA/NCI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Dec 2;468(7324):653-8. doi: 10.1038/nature09571.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21124450" target="_blank"〉PubMed〈/a〉
    Keywords: AMP-Activated Protein Kinases/chemistry/deficiency/genetics/metabolism ; Aneuploidy ; Animals ; Catalytic Domain/genetics ; Cell Cycle/*physiology ; Cell Death ; Cell Division ; Cell Survival ; Centrosome/pathology ; Energy Metabolism/*physiology ; Enzyme Activation ; Female ; Gene Deletion ; Hematopoietic Stem Cells/*cytology/drug effects/*metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Mitochondria/metabolism/pathology ; Multiprotein Complexes ; Pancytopenia/genetics ; Protein-Serine-Threonine Kinases/deficiency/genetics/*metabolism ; Proteins/metabolism ; Regeneration ; Signal Transduction ; Sirolimus/pharmacology ; Spindle Apparatus/pathology ; TOR Serine-Threonine Kinases/metabolism
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  • 49
    Publication Date: 2010-10-12
    Description: DNA glycosylases that remove alkylated and deaminated purine nucleobases are essential DNA repair enzymes that protect the genome, and at the same time confound cancer alkylation therapy, by excising cytotoxic N3-methyladenine bases formed by DNA-targeting anticancer compounds. The basis for glycosylase specificity towards N3- and N7-alkylpurines is believed to result from intrinsic instability of the modified bases and not from direct enzyme functional group chemistry. Here we present crystal structures of the recently discovered Bacillus cereus AlkD glycosylase in complex with DNAs containing alkylated, mismatched and abasic nucleotides. Unlike other glycosylases, AlkD captures the extrahelical lesion in a solvent-exposed orientation, providing an illustration for how hydrolysis of N3- and N7-alkylated bases may be facilitated by increased lifetime out of the DNA helix. The structures and supporting biochemical analysis of base flipping and catalysis reveal how the HEAT repeats of AlkD distort the DNA backbone to detect non-Watson-Crick base pairs without duplex intercalation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4160814/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4160814/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rubinson, Emily H -- Gowda, A S Prakasha -- Spratt, Thomas E -- Gold, Barry -- Eichman, Brandt F -- P30 CA068485/CA/NCI NIH HHS/ -- P30 ES000267/ES/NIEHS NIH HHS/ -- R01 CA029088/CA/NCI NIH HHS/ -- R01 CA29088/CA/NCI NIH HHS/ -- T32 ES007028/ES/NIEHS NIH HHS/ -- England -- Nature. 2010 Nov 18;468(7322):406-11. doi: 10.1038/nature09428. Epub 2010 Oct 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20927102" target="_blank"〉PubMed〈/a〉
    Keywords: Alkylation ; Bacillus cereus/*enzymology ; Base Sequence ; Biocatalysis ; Crystallography, X-Ray ; DNA/chemistry/genetics/*metabolism ; *DNA Damage ; DNA Glycosylases/*metabolism ; DNA Repair/*physiology ; Hydrolysis ; Models, Molecular ; Nucleic Acid Conformation ; Protein Binding ; Solvents/chemistry ; Thermodynamics
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  • 50
    Publication Date: 2010-02-05
    Description: The M2 protein of influenza A virus is a membrane-spanning tetrameric proton channel targeted by the antiviral drugs amantadine and rimantadine. Resistance to these drugs has compromised their effectiveness against many influenza strains, including pandemic H1N1. A recent crystal structure of M2(22-46) showed electron densities attributed to a single amantadine in the amino-terminal half of the pore, indicating a physical occlusion mechanism for inhibition. However, a solution NMR structure of M2(18-60) showed four rimantadines bound to the carboxy-terminal lipid-facing surface of the helices, suggesting an allosteric mechanism. Here we show by solid-state NMR spectroscopy that two amantadine-binding sites exist in M2 in phospholipid bilayers. The high-affinity site, occupied by a single amantadine, is located in the N-terminal channel lumen, surrounded by residues mutated in amantadine-resistant viruses. Quantification of the protein-amantadine distances resulted in a 0.3 A-resolution structure of the high-affinity binding site. The second, low-affinity, site was observed on the C-terminal protein surface, but only when the drug reaches high concentrations in the bilayer. The orientation and dynamics of the drug are distinct in the two sites, as shown by (2)H NMR. These results indicate that amantadine physically occludes the M2 channel, thus paving the way for developing new antiviral drugs against influenza viruses. The study demonstrates the ability of solid-state NMR to elucidate small-molecule interactions with membrane proteins and determine high-resolution structures of their complexes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818718/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818718/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cady, Sarah D -- Schmidt-Rohr, Klaus -- Wang, Jun -- Soto, Cinque S -- Degrado, William F -- Hong, Mei -- AI74571/AI/NIAID NIH HHS/ -- GM088204/GM/NIGMS NIH HHS/ -- GM56423/GM/NIGMS NIH HHS/ -- R01 GM056423/GM/NIGMS NIH HHS/ -- R01 GM056423-12/GM/NIGMS NIH HHS/ -- R01 GM088204/GM/NIGMS NIH HHS/ -- R01 GM088204-01/GM/NIGMS NIH HHS/ -- U01 AI074571/AI/NIAID NIH HHS/ -- U01 AI074571-02/AI/NIAID NIH HHS/ -- England -- Nature. 2010 Feb 4;463(7281):689-92. doi: 10.1038/nature08722.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Iowa State University, Ames, Iowa 50011 2, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20130653" target="_blank"〉PubMed〈/a〉
    Keywords: Amantadine/chemistry/*metabolism/pharmacology ; Amino Acid Sequence ; Antiviral Agents/chemistry/*metabolism/pharmacology ; Binding Sites ; Crystallography, X-Ray ; Dimyristoylphosphatidylcholine/chemistry/metabolism ; Hydrogen-Ion Concentration ; Influenza A virus/*chemistry/drug effects ; Lipid Bilayers/chemistry/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation ; Structure-Activity Relationship ; Temperature ; Viral Matrix Proteins/antagonists & inhibitors/*chemistry/*metabolism
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  • 51
    Publication Date: 2010-05-28
    Description: Complex I is the first enzyme of the respiratory chain and has a central role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation by an unknown mechanism. Dysfunction of complex I has been implicated in many human neurodegenerative diseases. We have determined the structure of its hydrophilic domain previously. Here, we report the alpha-helical structure of the membrane domain of complex I from Escherichia coli at 3.9 A resolution. The antiporter-like subunits NuoL/M/N each contain 14 conserved transmembrane (TM) helices. Two of them are discontinuous, as in some transporters. Unexpectedly, subunit NuoL also contains a 110-A long amphipathic alpha-helix, spanning almost the entire length of the domain. Furthermore, we have determined the structure of the entire complex I from Thermus thermophilus at 4.5 A resolution. The L-shaped assembly consists of the alpha-helical model for the membrane domain, with 63 TM helices, and the known structure of the hydrophilic domain. The architecture of the complex provides strong clues about the coupling mechanism: the conformational changes at the interface of the two main domains may drive the long amphipathic alpha-helix of NuoL in a piston-like motion, tilting nearby discontinuous TM helices, resulting in proton translocation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Efremov, Rouslan G -- Baradaran, Rozbeh -- Sazanov, Leonid A -- MC_U105674180/Medical Research Council/United Kingdom -- Medical Research Council/United Kingdom -- England -- Nature. 2010 May 27;465(7297):441-5. doi: 10.1038/nature09066.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20505720" target="_blank"〉PubMed〈/a〉
    Keywords: Benzoquinones/metabolism ; Binding Sites ; Cell Membrane/metabolism ; Crystallography, X-Ray ; Electron Transport Complex I/*chemistry/*metabolism ; Escherichia coli/*enzymology ; Models, Molecular ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein Subunits/*chemistry/*metabolism ; Structure-Activity Relationship ; Thermus thermophilus/*enzymology
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  • 52
    Publication Date: 2010-04-09
    Description: Gut microbes supply the human body with energy from dietary polysaccharides through carbohydrate active enzymes, or CAZymes, which are absent in the human genome. These enzymes target polysaccharides from terrestrial plants that dominated diet throughout human evolution. The array of CAZymes in gut microbes is highly diverse, exemplified by the human gut symbiont Bacteroides thetaiotaomicron, which contains 261 glycoside hydrolases and polysaccharide lyases, as well as 208 homologues of susC and susD-genes coding for two outer membrane proteins involved in starch utilization. A fundamental question that, to our knowledge, has yet to be addressed is how this diversity evolved by acquiring new genes from microbes living outside the gut. Here we characterize the first porphyranases from a member of the marine Bacteroidetes, Zobellia galactanivorans, active on the sulphated polysaccharide porphyran from marine red algae of the genus Porphyra. Furthermore, we show that genes coding for these porphyranases, agarases and associated proteins have been transferred to the gut bacterium Bacteroides plebeius isolated from Japanese individuals. Our comparative gut metagenome analyses show that porphyranases and agarases are frequent in the Japanese population and that they are absent in metagenome data from North American individuals. Seaweeds make an important contribution to the daily diet in Japan (14.2 g per person per day), and Porphyra spp. (nori) is the most important nutritional seaweed, traditionally used to prepare sushi. This indicates that seaweeds with associated marine bacteria may have been the route by which these novel CAZymes were acquired in human gut bacteria, and that contact with non-sterile food may be a general factor in CAZyme diversity in human gut microbes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hehemann, Jan-Hendrik -- Correc, Gaelle -- Barbeyron, Tristan -- Helbert, William -- Czjzek, Mirjam -- Michel, Gurvan -- England -- Nature. 2010 Apr 8;464(7290):908-12. doi: 10.1038/nature08937.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universite Pierre et Marie Curie, Paris, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20376150" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Physiological/physiology ; Bacteroides/*enzymology/genetics ; Biological Evolution ; Crystallography, X-Ray ; Cultural Diversity ; Diet ; Eukaryota/chemistry/metabolism ; Feces/enzymology/microbiology ; *Food Microbiology ; Gene Transfer, Horizontal ; Genome, Bacterial/genetics ; Glycoside Hydrolases/chemistry/isolation & purification/*metabolism ; Humans ; Intestines/*microbiology ; Japan ; *Marine Biology ; *Metagenome ; Models, Molecular ; North America ; Phylogeny ; Porphyra/chemistry/metabolism/microbiology ; Protein Conformation ; Sepharose/*analogs & derivatives/chemistry/metabolism ; Substrate Specificity
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  • 53
    Publication Date: 2010-10-15
    Description: Eukaryotes and archaea use a protease called the proteasome that has an integral role in maintaining cellular function through the selective degradation of proteins. Proteolysis occurs in a barrel-shaped 20S core particle, which in Thermoplasma acidophilum is built from four stacked homoheptameric rings of subunits, alpha and beta, arranged alpha(7)beta(7)beta(7)alpha(7) (ref. 5). These rings form three interconnected cavities, including a pair of antechambers (formed by alpha(7)beta(7)) through which substrates are passed before degradation and a catalytic chamber (beta(7)beta(7)) where the peptide-bond hydrolysis reaction occurs. Although it is clear that substrates must be unfolded to enter through narrow, gated passageways (13 A in diameter) located on the alpha-rings, the structural and dynamical properties of substrates inside the proteasome antechamber remain unclear. Confinement in the antechamber might be expected to promote folding and thus impede proteolysis. Here we investigate the folding, stability and dynamics of three small protein substrates in the antechamber by methyl transverse-relaxation-optimized NMR spectroscopy. We show that these substrates interact actively with the antechamber walls and have drastically altered kinetic and equilibrium properties that maintain them in unstructured states so as to be accessible for hydrolysis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ruschak, Amy M -- Religa, Tomasz L -- Breuer, Sarah -- Witt, Susanne -- Kay, Lewis E -- Canadian Institutes of Health Research/Canada -- England -- Nature. 2010 Oct 14;467(7317):868-71. doi: 10.1038/nature09444.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944750" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Hydrolysis ; Kinetics ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Proteasome Endopeptidase Complex/*chemistry/*metabolism ; Protein Folding ; *Protein Processing, Post-Translational ; Protein Stability ; Protein Subunits/chemistry/metabolism ; *Protein Unfolding ; Thermodynamics ; Thermoplasma/enzymology
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  • 54
    Publication Date: 2010-07-24
    Description: Graphene nanoribbons-narrow and straight-edged stripes of graphene, or single-layer graphite-are predicted to exhibit electronic properties that make them attractive for the fabrication of nanoscale electronic devices. In particular, although the two-dimensional parent material graphene exhibits semimetallic behaviour, quantum confinement and edge effects should render all graphene nanoribbons with widths smaller than 10 nm semiconducting. But exploring the potential of graphene nanoribbons is hampered by their limited availability: although they have been made using chemical, sonochemical and lithographic methods as well as through the unzipping of carbon nanotubes, the reliable production of graphene nanoribbons smaller than 10 nm with chemical precision remains a significant challenge. Here we report a simple method for the production of atomically precise graphene nanoribbons of different topologies and widths, which uses surface-assisted coupling of molecular precursors into linear polyphenylenes and their subsequent cyclodehydrogenation. The topology, width and edge periphery of the graphene nanoribbon products are defined by the structure of the precursor monomers, which can be designed to give access to a wide range of different graphene nanoribbons. We expect that our bottom-up approach to the atomically precise fabrication of graphene nanoribbons will finally enable detailed experimental investigations of the properties of this exciting class of materials. It should even provide a route to graphene nanoribbon structures with engineered chemical and electronic properties, including the theoretically predicted intraribbon quantum dots, superlattice structures and magnetic devices based on specific graphene nanoribbon edge states.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cai, Jinming -- Ruffieux, Pascal -- Jaafar, Rached -- Bieri, Marco -- Braun, Thomas -- Blankenburg, Stephan -- Muoth, Matthias -- Seitsonen, Ari P -- Saleh, Moussa -- Feng, Xinliang -- Mullen, Klaus -- Fasel, Roman -- England -- Nature. 2010 Jul 22;466(7305):470-3. doi: 10.1038/nature09211.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun and 8600 Dubendorf, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20651687" target="_blank"〉PubMed〈/a〉
    Keywords: Electronics/*instrumentation ; Graphite/*chemistry ; Hydrogenation ; Models, Molecular ; Molecular Conformation ; Nanotubes, Carbon/*chemistry
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  • 55
    Publication Date: 2010-06-01
    Description: In termination of protein synthesis, the bacterial release factors RF1 and RF2 bind to the ribosome through specific recognition of messenger RNA stop codons and trigger hydrolysis of the bond between the nascent polypeptide and the transfer RNA at the peptidyl-tRNA site, thereby releasing the newly synthesized protein. The release factors are highly specific for a U in the first stop-codon position and recognize different combinations of purines in the second and third positions, with RF1 reading UAA and UAG and RF2 reading UAA and UGA. With recently determined crystal structures of termination complexes, it has become possible to decipher the energetics of stop-codon reading by computational analysis and to clarify the origin of the high release-factor binding accuracy. Here we report molecular dynamics free-energy calculations on different cognate and non-cognate termination complexes. The simulations quantitatively explain the basic principles of decoding in all three codon positions and reveal the key elements responsible for specificity of the release factors. The overall reading mechanism involves hitherto unidentified interactions and recognition switches that cannot be described in terms of a tripeptide anticodon model. Further simulations of complexes with tRNA(Trp), the tRNA recognizing the triplet codon for Trp, explain the observation of a 'leaky' stop codon and highlight the fundamentally different third position reading by RF2, which leads to a high stop-codon specificity with strong discrimination against the Trp codon. The simulations clearly illustrate the versatility of codon reading by protein, which goes far beyond tRNA mimicry.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sund, Johan -- Ander, Martin -- Aqvist, Johan -- England -- Nature. 2010 Jun 17;465(7300):947-50. doi: 10.1038/nature09082. Epub 2010 May 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Box 596, SE-751 24 Uppsala, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20512119" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteria/chemistry/genetics/*metabolism ; Codon, Terminator/*chemistry/genetics/*metabolism ; Models, Molecular ; Molecular Dynamics Simulation ; Peptide Termination Factors/chemistry/genetics/*metabolism ; Protein Binding/genetics ; Protein Structure, Tertiary ; RNA, Transfer/metabolism ; Ribosomes/genetics/*metabolism
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  • 56
    Publication Date: 2010-11-12
    Description: Mononuclear iron-containing oxygenases conduct a diverse variety of oxidation functions in biology, including the oxidative demethylation of methylated nucleic acids and histones. Escherichia coli AlkB is the first such enzyme that was discovered to repair methylated nucleic acids, which are otherwise cytotoxic and/or mutagenic. AlkB human homologues are known to play pivotal roles in various processes. Here we present structural characterization of oxidation intermediates for these demethylases. Using a chemical cross-linking strategy, complexes of AlkB-double stranded DNA (dsDNA) containing 1,N(6)-etheno adenine (epsilonA), N(3)-methyl thymine (3-meT) and N(3)-methyl cytosine (3-meC) are stabilized and crystallized, respectively. Exposing these crystals, grown under anaerobic conditions containing iron(II) and alpha-ketoglutarate (alphaKG), to dioxygen initiates oxidation in crystallo. Glycol (from epsilonA) and hemiaminal (from 3-meT) intermediates are captured; a zwitterionic intermediate (from 3-meC) is also proposed, based on crystallographic observations and computational analysis. The observation of these unprecedented intermediates provides direct support for the oxidative demethylation mechanism for these demethylases. This study also depicts a general mechanistic view of how a methyl group is oxidatively removed from different biological substrates.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058853/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058853/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yi, Chengqi -- Jia, Guifang -- Hou, Guanhua -- Dai, Qing -- Zhang, Wen -- Zheng, Guanqun -- Jian, Xing -- Yang, Cai-Guang -- Cui, Qiang -- He, Chuan -- GM071440/GM/NIGMS NIH HHS/ -- GM084028/GM/NIGMS NIH HHS/ -- R01 GM071440/GM/NIGMS NIH HHS/ -- R01 GM071440-06/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Nov 11;468(7321):330-3. doi: 10.1038/nature09497.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21068844" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Cross-Linking Reagents/chemistry ; Crystallization ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; *DNA Repair ; DNA Repair Enzymes/metabolism ; Dioxygenases/chemistry/*metabolism ; Escherichia coli/*enzymology ; Escherichia coli Proteins/chemistry/*metabolism ; Humans ; Iron/*metabolism ; Ketoglutaric Acids/metabolism ; Methylation ; Mixed Function Oxygenases/chemistry/*metabolism ; Models, Molecular ; Oxidation-Reduction ; Static Electricity ; Substrate Specificity
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  • 57
    Publication Date: 2010-04-13
    Description: Rhodopsin is a prototypical heptahelical family A G-protein-coupled receptor (GPCR) responsible for dim-light vision. Light isomerizes rhodopsin's retinal chromophore and triggers concerted movements of transmembrane helices, including an outward tilting of helix 6 (H6) and a smaller movement of H5, to create a site for G-protein binding and activation. However, the precise temporal sequence and mechanism underlying these helix rearrangements is unclear. We used site-directed non-natural amino acid mutagenesis to engineer rhodopsin with p-azido-l-phenylalanine residues incorporated at selected sites, and monitored the azido vibrational signatures using infrared spectroscopy as rhodopsin proceeded along its activation pathway. Here we report significant changes in electrostatic environments of the azido probes even in the inactive photoproduct Meta I, well before the active receptor state was formed. These early changes suggest a significant rotation of H6 and movement of the cytoplasmic part of H5 away from H3. Subsequently, a large outward tilt of H6 leads to opening of the cytoplasmic surface to form the active receptor photoproduct Meta II. Thus, our results reveal early conformational changes that precede larger rigid-body helix movements, and provide a basis to interpret recent GPCR crystal structures and to understand conformational sub-states observed during the activation of other GPCRs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ye, Shixin -- Zaitseva, Ekaterina -- Caltabiano, Gianluigi -- Schertler, Gebhard F X -- Sakmar, Thomas P -- Deupi, Xavier -- Vogel, Reiner -- England -- Nature. 2010 Apr 29;464(7293):1386-9. doi: 10.1038/nature08948. Epub 2010 Apr 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology and Biochemistry, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20383122" target="_blank"〉PubMed〈/a〉
    Keywords: Azides/analysis/*metabolism/radiation effects ; Cell Line ; Humans ; *Infrared Rays ; Models, Molecular ; Movement ; Phenylalanine/*analogs & derivatives/analysis/genetics/metabolism/radiation ; effects ; Protein Conformation ; Rhodopsin/chemistry/*genetics/*metabolism ; Spectroscopy, Fourier Transform Infrared ; Static Electricity ; Vibration
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  • 58
    Publication Date: 2010-10-15
    Description: The Ndc80 complex is a key site of regulated kinetochore-microtubule attachment (a process required for cell division), but the molecular mechanism underlying its function remains unknown. Here we present a subnanometre-resolution cryo-electron microscopy reconstruction of the human Ndc80 complex bound to microtubules, sufficient for precise docking of crystal structures of the component proteins. We find that the Ndc80 complex binds the microtubule with a tubulin monomer repeat, recognizing alpha- and beta-tubulin at both intra- and inter-tubulin dimer interfaces in a manner that is sensitive to tubulin conformation. Furthermore, Ndc80 complexes self-associate along protofilaments through interactions mediated by the amino-terminal tail of the NDC80 protein, which is the site of phospho-regulation by Aurora B kinase. The complex's mode of interaction with the microtubule and its oligomerization suggest a mechanism by which Aurora B could regulate the stability of load-bearing kinetochore-microtubule attachments.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957311/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957311/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Alushin, Gregory M -- Ramey, Vincent H -- Pasqualato, Sebastiano -- Ball, David A -- Grigorieff, Nikolaus -- Musacchio, Andrea -- Nogales, Eva -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Oct 14;467(7317):805-10. doi: 10.1038/nature09423.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biophysics Graduate Group, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944740" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Cryoelectron Microscopy ; Humans ; Kinetochores/*chemistry/ultrastructure ; Microtubules/chemistry/*metabolism/ultrastructure ; Mitosis ; Models, Biological ; Models, Molecular ; Nuclear Proteins/*chemistry/*metabolism/ultrastructure ; Protein Conformation ; Tubulin/chemistry/metabolism/ultrastructure
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  • 59
    Publication Date: 2010-06-26
    Description: Tumour-necrosis factor (TNF) receptor-associated factor 2 (TRAF2) is a key component in NF-kappaB signalling triggered by TNF-alpha. Genetic evidence indicates that TRAF2 is necessary for the polyubiquitination of receptor interacting protein 1 (RIP1) that then serves as a platform for recruitment and stimulation of IkappaB kinase, leading to activation of the transcription factor NF-kappaB. Although TRAF2 is a RING domain ubiquitin ligase, direct evidence that TRAF2 catalyses the ubiquitination of RIP1 is lacking. TRAF2 binds to sphingosine kinase 1 (SphK1), one of the isoenzymes that generates the pro-survival lipid mediator sphingosine-1-phosphate (S1P) inside cells. Here we show that SphK1 and the production of S1P is necessary for lysine-63-linked polyubiquitination of RIP1, phosphorylation of IkappaB kinase and IkappaBalpha, and IkappaBalpha degradation, leading to NF-kappaB activation. These responses were mediated by intracellular S1P independently of its cell surface G-protein-coupled receptors. S1P specifically binds to TRAF2 at the amino-terminal RING domain and stimulates its E3 ligase activity. S1P, but not dihydro-S1P, markedly increased recombinant TRAF2-catalysed lysine-63-linked, but not lysine-48-linked, polyubiquitination of RIP1 in vitro in the presence of the ubiquitin conjugating enzymes (E2) UbcH13 or UbcH5a. Our data show that TRAF2 is a novel intracellular target of S1P, and that S1P is the missing cofactor for TRAF2 E3 ubiquitin ligase activity, indicating a new paradigm for the regulation of lysine-63-linked polyubiquitination. These results also highlight the key role of SphK1 and its product S1P in TNF-alpha signalling and the canonical NF-kappaB activation pathway important in inflammatory, antiapoptotic and immune processes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946785/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946785/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Alvarez, Sergio E -- Harikumar, Kuzhuvelil B -- Hait, Nitai C -- Allegood, Jeremy -- Strub, Graham M -- Kim, Eugene Y -- Maceyka, Michael -- Jiang, Hualiang -- Luo, Cheng -- Kordula, Tomasz -- Milstien, Sheldon -- Spiegel, Sarah -- R01 AI050094/AI/NIAID NIH HHS/ -- R01 AI050094-09/AI/NIAID NIH HHS/ -- R01 CA061774/CA/NCI NIH HHS/ -- R01 CA061774-15/CA/NCI NIH HHS/ -- R01 CA061774-16/CA/NCI NIH HHS/ -- R01AI50094/AI/NIAID NIH HHS/ -- R01CA61774/CA/NCI NIH HHS/ -- R37 GM043880/GM/NIGMS NIH HHS/ -- R37 GM043880-18/GM/NIGMS NIH HHS/ -- R37 GM043880-19/GM/NIGMS NIH HHS/ -- R37 GM043880-20/GM/NIGMS NIH HHS/ -- R37 GM043880-21/GM/NIGMS NIH HHS/ -- R37GM043880/GM/NIGMS NIH HHS/ -- U19 AI077435/AI/NIAID NIH HHS/ -- U19 AI077435-020004/AI/NIAID NIH HHS/ -- U19 AI077435-02S10004/AI/NIAID NIH HHS/ -- U19 AI077435-030004/AI/NIAID NIH HHS/ -- U19AI077435/AI/NIAID NIH HHS/ -- England -- Nature. 2010 Jun 24;465(7301):1084-8. doi: 10.1038/nature09128.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, 1101 E. Marshall Street, Richmond, Virginia 23298, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20577214" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biocatalysis ; Cell Line ; Enzyme Activation ; Humans ; I-kappa B Kinase/metabolism ; I-kappa B Proteins/metabolism ; Lysine/metabolism ; Lysophospholipids/biosynthesis/chemistry/*metabolism ; Mice ; Models, Molecular ; NF-kappa B/metabolism ; Phosphorylation ; Phosphotransferases (Alcohol Group Acceptor)/genetics/metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptor-Interacting Protein Serine-Threonine Kinases/metabolism ; Sphingosine/*analogs & derivatives/biosynthesis/chemistry/metabolism ; Substrate Specificity ; TNF Receptor-Associated Factor 2/chemistry/*metabolism ; Tumor Necrosis Factor-alpha/pharmacology ; Ubiquitin-Conjugating Enzymes/metabolism ; Ubiquitin-Protein Ligases/*metabolism ; Ubiquitination/drug effects
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  • 60
    Publication Date: 2010-03-05
    Description: Innate immunity provides the first line of defence against invading pathogens and provides important cues for the development of adaptive immunity. Type-2 immunity-responsible for protective immune responses to helminth parasites and the underlying cause of the pathogenesis of allergic asthma-consists of responses dominated by the cardinal type-2 cytokines interleukin (IL)4, IL5 and IL13 (ref. 5). T cells are an important source of these cytokines in adaptive immune responses, but the innate cell sources remain to be comprehensively determined. Here, through the use of novel Il13-eGFP reporter mice, we present the identification and functional characterization of a new innate type-2 immune effector leukocyte that we have named the nuocyte. Nuocytes expand in vivo in response to the type-2-inducing cytokines IL25 and IL33, and represent the predominant early source of IL13 during helminth infection with Nippostrongylus brasiliensis. In the combined absence of IL25 and IL33 signalling, nuocytes fail to expand, resulting in a severe defect in worm expulsion that is rescued by the adoptive transfer of in vitro cultured wild-type, but not IL13-deficient, nuocytes. Thus, nuocytes represent a critically important innate effector cell in type-2 immunity.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862165/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862165/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Neill, Daniel R -- Wong, See Heng -- Bellosi, Agustin -- Flynn, Robin J -- Daly, Maria -- Langford, Theresa K A -- Bucks, Christine -- Kane, Colleen M -- Fallon, Padraic G -- Pannell, Richard -- Jolin, Helen E -- McKenzie, Andrew N J -- MC_U105178805/Medical Research Council/United Kingdom -- U.1051.03.007(78805)/Medical Research Council/United Kingdom -- England -- Nature. 2010 Apr 29;464(7293):1367-70. doi: 10.1038/nature08900. Epub 2010 Mar 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20200518" target="_blank"〉PubMed〈/a〉
    Keywords: Adoptive Transfer ; Animals ; Cells, Cultured ; Immunity, Innate/*immunology ; Interleukin-13/biosynthesis/deficiency/genetics ; Interleukin-17/deficiency/genetics ; Interleukins/biosynthesis/deficiency/genetics/*immunology ; Leukocytes/cytology/*immunology/metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Nippostrongylus/immunology ; Strongylida Infections/immunology ; Th2 Cells/*immunology
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  • 61
    Publication Date: 2010-12-03
    Description: The multi-subunit DNA-dependent RNA polymerase (RNAP) is the principal enzyme of transcription for gene expression. Transcription is regulated by various transcription factors. Gre factor homologue 1 (Gfh1), found in the Thermus genus, is a close homologue of the well-conserved bacterial transcription factor GreA, and inhibits transcription initiation and elongation by binding directly to RNAP. The structural basis of transcription inhibition by Gfh1 has remained elusive, although the crystal structures of RNAP and Gfh1 have been determined separately. Here we report the crystal structure of Thermus thermophilus RNAP complexed with Gfh1. The amino-terminal coiled-coil domain of Gfh1 fully occludes the channel formed between the two central modules of RNAP; this channel would normally be used for nucleotide triphosphate (NTP) entry into the catalytic site. Furthermore, the tip of the coiled-coil domain occupies the NTP beta-gamma phosphate-binding site. The NTP-entry channel is expanded, because the central modules are 'ratcheted' relative to each other by approximately 7 degrees , as compared with the previously reported elongation complexes. This 'ratcheted state' is an alternative structural state, defined by a newly acquired contact between the central modules. Therefore, the shape of Gfh1 is appropriate to maintain RNAP in the ratcheted state. Simultaneously, the ratcheting expands the nucleic-acid-binding channel, and kinks the bridge helix, which connects the central modules. Taken together, the present results reveal that Gfh1 inhibits transcription by preventing NTP binding and freezing RNAP in the alternative structural state. The ratcheted state might also be associated with other aspects of transcription, such as RNAP translocation and transcription termination.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tagami, Shunsuke -- Sekine, Shun-Ichi -- Kumarevel, Thirumananseri -- Hino, Nobumasa -- Murayama, Yuko -- Kamegamori, Syunsuke -- Yamamoto, Masaki -- Sakamoto, Kensaku -- Yokoyama, Shigeyuki -- England -- Nature. 2010 Dec 16;468(7326):978-82. doi: 10.1038/nature09573. Epub 2010 Dec 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21124318" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; DNA-Directed RNA Polymerases/*chemistry/*metabolism ; Models, Molecular ; Protein Conformation ; Thermus thermophilus/chemistry/*enzymology ; *Transcription, Genetic
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  • 62
    Publication Date: 2010-03-20
    Description: Cobalamin (Cbl, vitamin B(12)) is a bacterial organic compound and an essential coenzyme in mammals, which take it up from the diet. This occurs by the combined action of the gastric intrinsic factor (IF) and the ileal endocytic cubam receptor formed by the 460-kilodalton (kDa) protein cubilin and the 45-kDa transmembrane protein amnionless. Loss of function of any of these proteins ultimately leads to Cbl deficiency in man. Here we present the crystal structure of the complex between IF-Cbl and the cubilin IF-Cbl-binding-region (CUB(5-8)) determined at 3.3 A resolution. The structure provides insight into how several CUB (for 'complement C1r/C1s, Uegf, Bmp1') domains collectively function as modular ligand-binding regions, and how two distant CUB domains embrace the Cbl molecule by binding the two IF domains in a Ca(2+)-dependent manner. This dual-point model provides a probable explanation of how Cbl indirectly induces ligand-receptor coupling. Finally, the comparison of Ca(2+)-binding CUB domains and the low-density lipoprotein (LDL) receptor-type A modules suggests that the electrostatic pairing of a basic ligand arginine/lysine residue with Ca(2+)-coordinating acidic aspartates/glutamates is a common theme of Ca(2+)-dependent ligand-receptor interactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Andersen, Christian Brix Folsted -- Madsen, Mette -- Storm, Tina -- Moestrup, Soren K -- Andersen, Gregers R -- England -- Nature. 2010 Mar 18;464(7287):445-8. doi: 10.1038/nature08874.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medical Biochemistry, Aarhus University, 8000 Aarhus C, Denmark.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20237569" target="_blank"〉PubMed〈/a〉
    Keywords: Aspartic Acid/metabolism ; Binding Sites ; Calcium/metabolism ; Crystallography, X-Ray ; Glutamic Acid/metabolism ; Humans ; Intrinsic Factor/*chemistry/*metabolism ; Ligands ; Models, Molecular ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Cell Surface/*chemistry/*metabolism ; Static Electricity ; Vitamin B 12/*chemistry/*metabolism
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  • 63
    Publication Date: 2010-06-11
    Description: Regulation of the expression of the human immunodeficiency virus (HIV) genome is accomplished in large part by controlling transcription elongation. The viral protein Tat hijacks the host cell's RNA polymerase II elongation control machinery through interaction with the positive transcription elongation factor, P-TEFb, and directs the factor to promote productive elongation of HIV mRNA. Here we describe the crystal structure of the Tat.P-TEFb complex containing HIV-1 Tat, human Cdk9 (also known as CDK9), and human cyclin T1 (also known as CCNT1). Tat adopts a structure complementary to the surface of P-TEFb and makes extensive contacts, mainly with the cyclin T1 subunit of P-TEFb, but also with the T-loop of the Cdk9 subunit. The structure provides a plausible explanation for the tolerance of Tat to sequence variations at certain sites. Importantly, Tat induces significant conformational changes in P-TEFb. This finding lays a foundation for the design of compounds that would specifically inhibit the Tat.P-TEFb complex and block HIV replication.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2885016/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2885016/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tahirov, Tahir H -- Babayeva, Nigar D -- Varzavand, Katayoun -- Cooper, Jeffrey J -- Sedore, Stanley C -- Price, David H -- AI074392/AI/NIAID NIH HHS/ -- GM082923/GM/NIGMS NIH HHS/ -- GM35500/GM/NIGMS NIH HHS/ -- P30CA036727/CA/NCI NIH HHS/ -- P41 RR015301/RR/NCRR NIH HHS/ -- P41 RR015301-075443/RR/NCRR NIH HHS/ -- R01 GM035500/GM/NIGMS NIH HHS/ -- R01 GM035500-20/GM/NIGMS NIH HHS/ -- R01 GM035500-21/GM/NIGMS NIH HHS/ -- R01 GM035500-22/GM/NIGMS NIH HHS/ -- R01 GM035500-23/GM/NIGMS NIH HHS/ -- R01 GM035500-24/GM/NIGMS NIH HHS/ -- R01 GM082923/GM/NIGMS NIH HHS/ -- R01 GM082923-01A2/GM/NIGMS NIH HHS/ -- R01 GM082923-02/GM/NIGMS NIH HHS/ -- R01 GM082923-02S1/GM/NIGMS NIH HHS/ -- R21 AI074392/AI/NIAID NIH HHS/ -- R21 AI074392-01A1/AI/NIAID NIH HHS/ -- R21 AI074392-02/AI/NIAID NIH HHS/ -- R33 AI074392/AI/NIAID NIH HHS/ -- R33 AI074392-03/AI/NIAID NIH HHS/ -- RR-15301/RR/NCRR NIH HHS/ -- England -- Nature. 2010 Jun 10;465(7299):747-51. doi: 10.1038/nature09131.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-7696, USA. ttahirov@unmc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20535204" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Amino Acid Sequence ; Animals ; Binding Sites ; Crystallography, X-Ray ; Cyclin T/chemistry/metabolism ; Cyclin-Dependent Kinase 9/chemistry/metabolism ; Enzyme Activation ; HIV-1/*chemistry ; Humans ; Models, Molecular ; Molecular Sequence Data ; Positive Transcriptional Elongation Factor B/*chemistry/*metabolism ; Protein Binding ; Protein Conformation ; tat Gene Products, Human Immunodeficiency Virus/*chemistry/genetics/*metabolism
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  • 64
    Publication Date: 2010-02-16
    Description: The in vivo, genetically programmed incorporation of designer amino acids allows the properties of proteins to be tailored with molecular precision. The Methanococcus jannaschii tyrosyl-transfer-RNA synthetase-tRNA(CUA) (MjTyrRS-tRNA(CUA)) and the Methanosarcina barkeri pyrrolysyl-tRNA synthetase-tRNA(CUA) (MbPylRS-tRNA(CUA)) orthogonal pairs have been evolved to incorporate a range of unnatural amino acids in response to the amber codon in Escherichia coli. However, the potential of synthetic genetic code expansion is generally limited to the low efficiency incorporation of a single type of unnatural amino acid at a time, because every triplet codon in the universal genetic code is used in encoding the synthesis of the proteome. To encode efficiently many distinct unnatural amino acids into proteins we require blank codons and mutually orthogonal aminoacyl-tRNA synthetase-tRNA pairs that recognize unnatural amino acids and decode the new codons. Here we synthetically evolve an orthogonal ribosome (ribo-Q1) that efficiently decodes a series of quadruplet codons and the amber codon, providing several blank codons on an orthogonal messenger RNA, which it specifically translates. By creating mutually orthogonal aminoacyl-tRNA synthetase-tRNA pairs and combining them with ribo-Q1 we direct the incorporation of distinct unnatural amino acids in response to two of the new blank codons on the orthogonal mRNA. Using this code, we genetically direct the formation of a specific, redox-insensitive, nanoscale protein cross-link by the bio-orthogonal cycloaddition of encoded azide- and alkyne-containing amino acids. Because the synthetase-tRNA pairs used have been evolved to incorporate numerous unnatural amino acids, it will be possible to encode more than 200 unnatural amino acid combinations using this approach. As ribo-Q1 independently decodes a series of quadruplet codons, this work provides foundational technologies for the encoded synthesis and synthetic evolution of unnatural polymers in cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Neumann, Heinz -- Wang, Kaihang -- Davis, Lloyd -- Garcia-Alai, Maria -- Chin, Jason W -- MC_U105181009/Medical Research Council/United Kingdom -- MC_UP_A024_1008/Medical Research Council/United Kingdom -- Medical Research Council/United Kingdom -- England -- Nature. 2010 Mar 18;464(7287):441-4. doi: 10.1038/nature08817. Epub 2010 Feb 14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20154731" target="_blank"〉PubMed〈/a〉
    Keywords: Alkynes/metabolism ; Amino Acids/genetics/*metabolism ; Amino Acyl-tRNA Synthetases/genetics/metabolism ; Azides/metabolism ; Biocatalysis/drug effects ; Calmodulin/chemistry/genetics/metabolism ; Codon/*genetics ; Copper/metabolism/pharmacology ; Cyclization/drug effects ; *Directed Molecular Evolution ; *Genetic Code/genetics ; Genetic Engineering/*methods ; Methanococcus ; Models, Molecular ; *Protein Biosynthesis/genetics/physiology ; Protein Conformation ; Protein Engineering/methods ; RNA, Messenger/genetics/metabolism ; RNA, Transfer/genetics/metabolism ; Ribosomes/chemistry/*metabolism
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  • 65
    Publication Date: 2010-02-12
    Description: Benzodiazepines are widely used in clinics and for recreational purposes, but will lead to addiction in vulnerable individuals. Addictive drugs increase the levels of dopamine and also trigger long-lasting synaptic adaptations in the mesolimbic reward system that ultimately may induce the pathological behaviour. The neural basis for the addictive nature of benzodiazepines, however, remains elusive. Here we show that benzodiazepines increase firing of dopamine neurons of the ventral tegmental area through the positive modulation of GABA(A) (gamma-aminobutyric acid type A) receptors in nearby interneurons. Such disinhibition, which relies on alpha1-containing GABA(A) receptors expressed in these cells, triggers drug-evoked synaptic plasticity in excitatory afferents onto dopamine neurons and underlies drug reinforcement. Taken together, our data provide evidence that benzodiazepines share defining pharmacological features of addictive drugs through cell-type-specific expression of alpha1-containing GABA(A) receptors in the ventral tegmental area. The data also indicate that subunit-selective benzodiazepines sparing alpha1 may be devoid of addiction liability.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871668/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871668/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tan, Kelly R -- Brown, Matthew -- Labouebe, Gwenael -- Yvon, Cedric -- Creton, Cyril -- Fritschy, Jean-Marc -- Rudolph, Uwe -- Luscher, Christian -- DA019022/DA/NIDA NIH HHS/ -- R01 DA019022/DA/NIDA NIH HHS/ -- R01 DA019022-04/DA/NIDA NIH HHS/ -- England -- Nature. 2010 Feb 11;463(7282):769-74. doi: 10.1038/nature08758.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Basic Neurosciences, Medical Faculty, University of Geneva, CH-1211 Geneva, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20148031" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials/drug effects ; Administration, Oral ; Animals ; Behavior, Addictive/*chemically induced/pathology/*physiopathology ; Benzodiazepines/administration & dosage/*adverse effects/*pharmacology ; Dopamine/metabolism ; Electric Conductivity ; Glutamic Acid/metabolism ; In Vitro Techniques ; Inhibitory Postsynaptic Potentials/drug effects/physiology ; Interneurons/drug effects/metabolism ; Mice ; Mice, Inbred C57BL ; Midazolam/administration & dosage/adverse effects/pharmacology ; Models, Biological ; Morphine/pharmacology ; Neuronal Plasticity/drug effects ; Neurons/*drug effects/metabolism ; Organ Specificity ; Receptors, AMPA/metabolism ; Receptors, GABA-A/deficiency/genetics/metabolism ; Substrate Specificity ; Ventral Tegmental Area/cytology/drug effects/metabolism ; gamma-Aminobutyric Acid/metabolism
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  • 66
    Publication Date: 2010-09-17
    Description: Apoptosis and the subsequent clearance of dying cells occurs throughout development and adult life in many tissues. Failure to promptly clear apoptotic cells has been linked to many diseases. ELMO1 is an evolutionarily conserved cytoplasmic engulfment protein that functions downstream of the phosphatidylserine receptor BAI1, and, along with DOCK1 and the GTPase RAC1, promotes internalization of the dying cells. Here we report the generation of ELMO1-deficient mice, which we found to be unexpectedly viable and grossly normal. However, they had a striking testicular pathology, with disrupted seminiferous epithelium, multinucleated giant cells, uncleared apoptotic germ cells and decreased sperm output. Subsequent in vitro and in vivo analyses revealed a crucial role for ELMO1 in the phagocytic clearance of apoptotic germ cells by Sertoli cells lining the seminiferous epithelium. The engulfment receptor BAI1 and RAC1 (upstream and downstream of ELMO1, respectively) were also important for Sertoli-cell-mediated engulfment. Collectively, these findings uncover a selective requirement for ELMO1 in Sertoli-cell-mediated removal of apoptotic germ cells and make a compelling case for a relationship between engulfment and tissue homeostasis in vivo.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773546/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773546/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Elliott, Michael R -- Zheng, Shuqiu -- Park, Daeho -- Woodson, Robin I -- Reardon, Michael A -- Juncadella, Ignacio J -- Kinchen, Jason M -- Zhang, Jun -- Lysiak, Jeffrey J -- Ravichandran, Kodi S -- R01 GM064709/GM/NIGMS NIH HHS/ -- R01 HD057242/HD/NICHD NIH HHS/ -- England -- Nature. 2010 Sep 16;467(7313):333-7. doi: 10.1038/nature09356.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia 22908, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20844538" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptor Proteins, Signal Transducing/deficiency/genetics/*metabolism ; Angiogenic Proteins/metabolism ; Animals ; *Apoptosis ; Cell Line ; Homeostasis ; Male ; Mice ; Mice, Inbred C57BL ; Neuropeptides/metabolism ; Phagocytosis/*physiology ; Phosphatidylserines/metabolism ; Seminiferous Epithelium/cytology/pathology ; Sertoli Cells/*cytology/*metabolism/pathology ; Signal Transduction ; Spermatozoa/*cytology/pathology ; rac GTP-Binding Proteins/metabolism ; rac1 GTP-Binding Protein
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  • 67
    Publication Date: 2010-10-15
    Description: The blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Armulik, Annika -- Genove, Guillem -- Mae, Maarja -- Nisancioglu, Maya H -- Wallgard, Elisabet -- Niaudet, Colin -- He, Liqun -- Norlin, Jenny -- Lindblom, Per -- Strittmatter, Karin -- Johansson, Bengt R -- Betsholtz, Christer -- England -- Nature. 2010 Nov 25;468(7323):557-61. doi: 10.1038/nature09522. Epub 2010 Oct 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medical Biochemistry and Biophysics, Division of Vascular Biology, Karolinska Institute, Scheeles vag 2, SE-171 77 Stockholm, Sweden. annika.armulik@ki.se〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944627" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astrocytes/metabolism ; Benzamides ; Blood-Brain Barrier/*cytology/*metabolism ; Central Nervous System/blood supply ; Endothelial Cells/metabolism ; Gene Expression Regulation ; Imatinib Mesylate ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Pericytes/*metabolism ; Piperazines/pharmacology ; Protein Kinase Inhibitors/pharmacology ; Pyrimidines/pharmacology ; Transcytosis/drug effects
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  • 68
    Publication Date: 2010-05-14
    Description: Nature's high-performance polymer, spider silk, consists of specific proteins, spidroins, with repetitive segments flanked by conserved non-repetitive domains. Spidroins are stored as a highly concentrated fluid dope. On silk formation, intermolecular interactions between repeat regions are established that provide strength and elasticity. How spiders manage to avoid premature spidroin aggregation before self-assembly is not yet established. A pH drop to 6.3 along the spider's spinning apparatus, altered salt composition and shear forces are believed to trigger the conversion to solid silk, but no molecular details are known. Miniature spidroins consisting of a few repetitive spidroin segments capped by the carboxy-terminal domain form metre-long silk-like fibres irrespective of pH. We discovered that incorporation of the amino-terminal domain of major ampullate spidroin 1 from the dragline of the nursery web spider Euprosthenops australis (NT) into mini-spidroins enables immediate, charge-dependent self-assembly at pH values around 6.3, but delays aggregation above pH 7. The X-ray structure of NT, determined to 1.7 A resolution, shows a homodimer of dipolar, antiparallel five-helix bundle subunits that lack homologues. The overall dimeric structure and observed charge distribution of NT is expected to be conserved through spider evolution and in all types of spidroins. Our results indicate a relay-like mechanism through which the N-terminal domain regulates spidroin assembly by inhibiting precocious aggregation during storage, and accelerating and directing self-assembly as the pH is lowered along the spider's silk extrusion duct.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Askarieh, Glareh -- Hedhammar, My -- Nordling, Kerstin -- Saenz, Alejandra -- Casals, Cristina -- Rising, Anna -- Johansson, Jan -- Knight, Stefan D -- England -- Nature. 2010 May 13;465(7295):236-8. doi: 10.1038/nature08962.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Oslo University, 1033 Blindern, 0315 Oslo, Norway.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463740" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Circular Dichroism ; Conserved Sequence ; Crystallography, X-Ray ; Hydrogen-Ion Concentration ; Models, Molecular ; Molecular Sequence Data ; Protein Structure, Tertiary ; Sequence Alignment ; Silk/*chemistry/*metabolism/ultrastructure ; Spiders/*chemistry ; Static Electricity
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  • 69
    Publication Date: 2010-11-12
    Description: Interaction of pathogens with cells of the immune system results in activation of inflammatory gene expression. This response, although vital for immune defence, is frequently deleterious to the host due to the exaggerated production of inflammatory proteins. The scope of inflammatory responses reflects the activation state of signalling proteins upstream of inflammatory genes as well as signal-induced assembly of nuclear chromatin complexes that support mRNA expression. Recognition of post-translationally modified histones by nuclear proteins that initiate mRNA transcription and support mRNA elongation is a critical step in the regulation of gene expression. Here we present a novel pharmacological approach that targets inflammatory gene expression by interfering with the recognition of acetylated histones by the bromodomain and extra terminal domain (BET) family of proteins. We describe a synthetic compound (I-BET) that by 'mimicking' acetylated histones disrupts chromatin complexes responsible for the expression of key inflammatory genes in activated macrophages, and confers protection against lipopolysaccharide-induced endotoxic shock and bacteria-induced sepsis. Our findings suggest that synthetic compounds specifically targeting proteins that recognize post-translationally modified histones can serve as a new generation of immunomodulatory drugs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nicodeme, Edwige -- Jeffrey, Kate L -- Schaefer, Uwe -- Beinke, Soren -- Dewell, Scott -- Chung, Chun-Wa -- Chandwani, Rohit -- Marazzi, Ivan -- Wilson, Paul -- Coste, Herve -- White, Julia -- Kirilovsky, Jorge -- Rice, Charles M -- Lora, Jose M -- Prinjha, Rab K -- Lee, Kevin -- Tarakhovsky, Alexander -- England -- Nature. 2010 Dec 23;468(7327):1119-23. doi: 10.1038/nature09589. Epub 2010 Nov 10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre de Recherche GSK, 27 Avenue du Quebec, 91140 Villebon Sur Yvette, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21068722" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylation/drug effects ; Animals ; Anti-Inflammatory Agents/chemistry/*pharmacology/therapeutic use ; Benzodiazepines ; Cells, Cultured ; Epigenomics ; Gene Expression Regulation/*drug effects ; Genome-Wide Association Study ; Heterocyclic Compounds with 4 or More Rings/chemistry/*pharmacology/therapeutic ; use ; Histone Deacetylase Inhibitors/pharmacology ; Hydroxamic Acids/pharmacology ; *Inflammation/drug therapy/prevention & control ; Kaplan-Meier Estimate ; Lipopolysaccharides/pharmacology ; Macrophages/*drug effects ; Mice ; Mice, Inbred C57BL ; Models, Molecular ; Protein Structure, Tertiary ; Protein-Serine-Threonine Kinases/metabolism ; Salmonella Infections/drug therapy/immunology/physiopathology/prevention & ; control ; Salmonella typhimurium ; Sepsis/drug therapy/prevention & control ; Shock, Septic/drug therapy/prevention & control
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  • 70
    Publication Date: 2010-07-09
    Description: Histone lysine acetylation and methylation have an important role during gene transcription in a chromatin context. Knowledge concerning the types of protein modules that can interact with acetyl-lysine has so far been limited to bromodomains. Recently, a tandem plant homeodomain (PHD) finger (PHD1-PHD2, or PHD12) of human DPF3b, which functions in association with the BAF chromatin remodelling complex to initiate gene transcription during heart and muscle development, was reported to bind histones H3 and H4 in an acetylation-sensitive manner, making it the first alternative to bromodomains for acetyl-lysine binding. Here we report the structural mechanism of acetylated histone binding by the double PHD fingers of DPF3b. Our three-dimensional solution structures and biochemical analysis of DPF3b highlight the molecular basis of the integrated tandem PHD finger, which acts as one functional unit in the sequence-specific recognition of lysine-14-acetylated histone H3 (H3K14ac). Whereas the interaction with H3 is promoted by acetylation at lysine 14, it is inhibited by methylation at lysine 4, and these opposing influences are important during transcriptional activation of the mouse DPF3b target genes Pitx2 and Jmjd1c. Binding of this tandem protein module to chromatin can thus be regulated by different histone modifications during the initiation of gene transcription.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901902/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901902/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zeng, Lei -- Zhang, Qiang -- Li, Side -- Plotnikov, Alexander N -- Walsh, Martin J -- Zhou, Ming-Ming -- R01 CA087658/CA/NCI NIH HHS/ -- R01 CA087658-10/CA/NCI NIH HHS/ -- R01 HG004508/HG/NHGRI NIH HHS/ -- R01 HG004508-02/HG/NHGRI NIH HHS/ -- England -- Nature. 2010 Jul 8;466(7303):258-62. doi: 10.1038/nature09139.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural and Chemical Biology, Mount Sinai School of Medicine, 1425 Madison Avenue, Box 1677, New York, New York 10029, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20613843" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylation ; Animals ; Cell Line ; DNA-Binding Proteins/*chemistry/genetics/*metabolism ; Histones/*chemistry/*metabolism ; Humans ; Lysine/chemistry/metabolism ; Mice ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Protein Folding ; Structure-Activity Relationship ; Substrate Specificity ; Thermodynamics ; Transcription Factors/*chemistry/genetics/*metabolism ; Transcription, Genetic ; Transcriptional Activation ; Up-Regulation ; *Zinc Fingers
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  • 71
    Publication Date: 2010-08-13
    Description: The eubacterial SOS system is a paradigm of cellular DNA damage and repair, and its activation can contribute to antibiotic resistance. Under normal conditions, LexA represses the transcription of many DNA repair proteins by binding to SOS 'boxes' in their operators. Under genotoxic stress, accumulating complexes of RecA, ATP and single-stranded DNA (ssDNA) activate LexA for autocleavage. To address how LexA recognizes its binding sites, we determined three crystal structures of Escherichia coli LexA in complex with SOS boxes. Here we report the structure of these LexA-DNA complexes. The DNA-binding domains of the LexA dimer interact with the DNA in the classical fashion of a winged helix-turn-helix motif. However, the wings of these two DNA-binding domains bind to the same minor groove of the DNA. These wing-wing contacts may explain why the spacing between the two half-sites of E. coli SOS boxes is invariant.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921665/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921665/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Adrianna P P -- Pigli, Ying Z -- Rice, Phoebe A -- GM058827/GM/NIGMS NIH HHS/ -- R01 GM058827/GM/NIGMS NIH HHS/ -- R01 GM058827-09/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Aug 12;466(7308):883-6. doi: 10.1038/nature09200.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20703307" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Bacterial Proteins/*chemistry/*metabolism ; Base Sequence ; Crystallography, X-Ray ; DNA Damage ; DNA Repair/genetics ; DNA, Bacterial/chemistry/*genetics/*metabolism ; Electrophoretic Mobility Shift Assay ; *Escherichia coli/chemistry/genetics ; Escherichia coli Proteins/chemistry/genetics/metabolism ; Models, Molecular ; Protein Binding ; *Protein Multimerization ; Protein Structure, Tertiary ; Rec A Recombinases/metabolism ; Repressor Proteins/chemistry/metabolism ; SOS Response (Genetics)/*genetics ; Serine Endopeptidases/*chemistry/*metabolism ; Winged-Helix Transcription Factors/chemistry/metabolism
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  • 72
    Publication Date: 2010-10-29
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Thomine, Sebastien -- Barbier-Brygoo, Helene -- England -- Nature. 2010 Oct 28;467(7319):1058-9. doi: 10.1038/4671058a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20981091" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arabidopsis/cytology/genetics/metabolism ; Arabidopsis Proteins/*chemistry/genetics/metabolism ; Bacterial Proteins/*chemistry/genetics/metabolism ; Crystallography, X-Ray ; Haemophilus influenzae/*chemistry/genetics ; Ion Channel Gating ; Membrane Proteins/*chemistry/genetics/metabolism ; Models, Molecular ; Phenylalanine/genetics/metabolism ; Plant Stomata/*metabolism ; Protein Folding ; *Structural Homology, Protein
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  • 73
    Publication Date: 2010-01-15
    Description: In an effort to find new pharmacological modalities to overcome resistance to ATP-binding-site inhibitors of Bcr-Abl, we recently reported the discovery of GNF-2, a selective allosteric Bcr-Abl inhibitor. Here, using solution NMR, X-ray crystallography, mutagenesis and hydrogen exchange mass spectrometry, we show that GNF-2 binds to the myristate-binding site of Abl, leading to changes in the structural dynamics of the ATP-binding site. GNF-5, an analogue of GNF-2 with improved pharmacokinetic properties, when used in combination with the ATP-competitive inhibitors imatinib or nilotinib, suppressed the emergence of resistance mutations in vitro, displayed additive inhibitory activity in biochemical and cellular assays against T315I mutant human Bcr-Abl and displayed in vivo efficacy against this recalcitrant mutant in a murine bone-marrow transplantation model. These results show that therapeutically relevant inhibition of Bcr-Abl activity can be achieved with inhibitors that bind to the myristate-binding site and that combining allosteric and ATP-competitive inhibitors can overcome resistance to either agent alone.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901986/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901986/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Jianming -- Adrian, Francisco J -- Jahnke, Wolfgang -- Cowan-Jacob, Sandra W -- Li, Allen G -- Iacob, Roxana E -- Sim, Taebo -- Powers, John -- Dierks, Christine -- Sun, Fangxian -- Guo, Gui-Rong -- Ding, Qiang -- Okram, Barun -- Choi, Yongmun -- Wojciechowski, Amy -- Deng, Xianming -- Liu, Guoxun -- Fendrich, Gabriele -- Strauss, Andre -- Vajpai, Navratna -- Grzesiek, Stephan -- Tuntland, Tove -- Liu, Yi -- Bursulaya, Badry -- Azam, Mohammad -- Manley, Paul W -- Engen, John R -- Daley, George Q -- Warmuth, Markus -- Gray, Nathanael S -- R01 CA130876/CA/NCI NIH HHS/ -- R01 CA130876-03/CA/NCI NIH HHS/ -- England -- Nature. 2010 Jan 28;463(7280):501-6. doi: 10.1038/nature08675. Epub 2010 Jan 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Dana-Farber Cancer Institute, Harvard Medical School, Department of Cancer Biology, Seeley G. Mudd Building 628, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20072125" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antineoplastic Agents/*chemistry/metabolism/*pharmacology ; Antineoplastic Combined Chemotherapy Protocols ; Benzamides ; Binding Sites ; Bone Marrow Transplantation ; Cell Line, Tumor ; Crystallization ; Disease Models, Animal ; Drug Resistance, Neoplasm/*drug effects ; Female ; Fusion Proteins, bcr-abl/*chemistry/genetics/metabolism ; Humans ; Imatinib Mesylate ; Inhibitory Concentration 50 ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug ; therapy/enzymology/*metabolism ; Male ; Mass Spectrometry ; Mice ; Models, Molecular ; Mutation/genetics ; Piperazines/chemistry/pharmacology ; Protein Structure, Tertiary ; Pyrimidines/chemistry/metabolism/pharmacology ; Transplantation, Heterologous
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  • 74
    Publication Date: 2010-01-22
    Description: Group II chaperonins are essential mediators of cellular protein folding in eukaryotes and archaea. These oligomeric protein machines, approximately 1 megadalton, consist of two back-to-back rings encompassing a central cavity that accommodates polypeptide substrates. Chaperonin-mediated protein folding is critically dependent on the closure of a built-in lid, which is triggered by ATP hydrolysis. The structural rearrangements and molecular events leading to lid closure are still unknown. Here we report four single particle cryo-electron microscopy (cryo-EM) structures of Mm-cpn, an archaeal group II chaperonin, in the nucleotide-free (open) and nucleotide-induced (closed) states. The 4.3 A resolution of the closed conformation allowed building of the first ever atomic model directly from the single particle cryo-EM density map, in which we were able to visualize the nucleotide and more than 70% of the side chains. The model of the open conformation was obtained by using the deformable elastic network modelling with the 8 A resolution open-state cryo-EM density restraints. Together, the open and closed structures show how local conformational changes triggered by ATP hydrolysis lead to an alteration of intersubunit contacts within and across the rings, ultimately causing a rocking motion that closes the ring. Our analyses show that there is an intricate and unforeseen set of interactions controlling allosteric communication and inter-ring signalling, driving the conformational cycle of group II chaperonins. Beyond this, we anticipate that our methodology of combining single particle cryo-EM and computational modelling will become a powerful tool in the determination of atomic details involved in the dynamic processes of macromolecular machines in solution.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834796/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834796/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Junjie -- Baker, Matthew L -- Schroder, Gunnar F -- Douglas, Nicholai R -- Reissmann, Stefanie -- Jakana, Joanita -- Dougherty, Matthew -- Fu, Caroline J -- Levitt, Michael -- Ludtke, Steven J -- Frydman, Judith -- Chiu, Wah -- P41 RR002250/RR/NCRR NIH HHS/ -- P41 RR002250-23/RR/NCRR NIH HHS/ -- P41 RR002250-237254/RR/NCRR NIH HHS/ -- P41 RR002250-24/RR/NCRR NIH HHS/ -- P41 RR002250-247897/RR/NCRR NIH HHS/ -- PN2 EY016525/EY/NEI NIH HHS/ -- PN2 EY016525-02S1/EY/NEI NIH HHS/ -- PN2 EY016525-03/EY/NEI NIH HHS/ -- PN2 EY016525-04/EY/NEI NIH HHS/ -- PN2 EY016525-05/EY/NEI NIH HHS/ -- R01 GM063817/GM/NIGMS NIH HHS/ -- R01 GM079429/GM/NIGMS NIH HHS/ -- R01 GM079429-03/GM/NIGMS NIH HHS/ -- R01 GM080139/GM/NIGMS NIH HHS/ -- R01 GM080139-03/GM/NIGMS NIH HHS/ -- R01 GM080139-04/GM/NIGMS NIH HHS/ -- R90 DK071504/DK/NIDDK NIH HHS/ -- R90 DK071504-03/DK/NIDDK NIH HHS/ -- T32 GM007276-30/GM/NIGMS NIH HHS/ -- T32 GM007276-31/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jan 21;463(7279):379-83. doi: 10.1038/nature08701.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20090755" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/chemistry/metabolism/pharmacology ; Allosteric Regulation ; Binding Sites ; Cryoelectron Microscopy ; Group II Chaperonins/*chemistry/*metabolism/ultrastructure ; Hydrolysis/drug effects ; Methanococcus/*chemistry ; Models, Molecular ; Protein Binding ; Protein Conformation/drug effects ; *Protein Folding ; Protein Subunits/chemistry/metabolism ; Structure-Activity Relationship
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  • 75
    Publication Date: 2010-08-03
    Description: The flagellar motor drives the rotation of flagellar filaments at hundreds of revolutions per second, efficiently propelling bacteria through viscous media. The motor uses the potential energy from an electrochemical gradient of cations across the cytoplasmic membrane to generate torque. A rapid switch from anticlockwise to clockwise rotation determines whether a bacterium runs smoothly forward or tumbles to change its trajectory. A protein called FliG forms a ring in the rotor of the flagellar motor that is involved in the generation of torque through an interaction with the cation-channel-forming stator subunit MotA. FliG has been suggested to adopt distinct conformations that induce switching but these structural changes and the molecular mechanism of switching are unknown. Here we report the molecular structure of the full-length FliG protein, identify conformational changes that are involved in rotational switching and uncover the structural basis for the formation of the FliG torque ring. This allows us to propose a model of the complete ring and switching mechanism in which conformational changes in FliG reverse the electrostatic charges involved in torque generation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3159035/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3159035/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, Lawrence K -- Ginsburg, Michael A -- Crovace, Claudia -- Donohoe, Mhairi -- Stock, Daniela -- MC_U105170645/Medical Research Council/United Kingdom -- P41 RR007707/RR/NCRR NIH HHS/ -- P41 RR007707-17/RR/NCRR NIH HHS/ -- RR007707/RR/NCRR NIH HHS/ -- Y1-CO-1020/CO/NCI NIH HHS/ -- Y1-GM-1104/GM/NIGMS NIH HHS/ -- Medical Research Council/United Kingdom -- England -- Nature. 2010 Aug 19;466(7309):996-1000. doi: 10.1038/nature09300. Epub 2010 Aug 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool Street, Darlinghurst, New South Wales 2010, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20676082" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Flagella/*chemistry/genetics/*physiology ; Models, Molecular ; Molecular Motor Proteins/*chemistry/genetics/metabolism ; Molecular Sequence Data ; Mutation ; Protein Conformation ; Protein Multimerization ; Protein Structure, Tertiary ; *Rotation ; Static Electricity ; Structure-Activity Relationship ; Thermotoga maritima/chemistry ; *Torque
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  • 76
    Publication Date: 2010-03-30
    Description: Cancer chemoprevention uses natural, synthetic, or biological substances to reverse, suppress, or prevent either the initial phase of carcinogenesis or the progression of neoplastic cells to cancer. It holds promise for overcoming problems associated with the treatment of late-stage cancers. However, the broad application of chemoprevention is compromised at present by limited effectiveness and potential toxicity. To overcome these challenges, here we developed a new chemoprevention approach that specifically targets premalignant tumour cells for apoptosis. We show that a deficiency in the adenomatous polyposis coli (APC) gene and subsequent activation of beta-catenin lead to the repression of cellular caspase-8 inhibitor c-FLIP (also known as CFLAR) expression through activation of c-Myc, and that all-trans-retinyl acetate (RAc) independently upregulates tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptors and suppresses decoy receptors. Thus, the combination of TRAIL and RAc induces apoptosis in APC-deficient premalignant cells without affecting normal cells in vitro. In addition, we show that short-term and non-continuous TRAIL and RAc treatment induce apoptosis specifically in intestinal polyps, strongly inhibit tumour growth, and prolong survival in multiple intestinal neoplasms C57BL/6J-Apc(Min)/J (Apc(Min)) mice. With our approach, we further demonstrate that TRAIL and RAc induce significant cell death in human colon polyps, providing a potentially selective approach for colorectal cancer chemoprevention by targeting APC-deficient cells for apoptosis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425353/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425353/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Ling -- Ren, Xiaoyang -- Alt, Eckhard -- Bai, Xiaowen -- Huang, Shaoyi -- Xu, Zhengming -- Lynch, Patrick M -- Moyer, Mary P -- Wen, Xian-Feng -- Wu, Xiangwei -- AI063063/AI/NIAID NIH HHS/ -- R01 AI063063/AI/NIAID NIH HHS/ -- England -- Nature. 2010 Apr 15;464(7291):1058-61. doi: 10.1038/nature08871. Epub 2010 Mar 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20348907" target="_blank"〉PubMed〈/a〉
    Keywords: Adenomatous Polyposis Coli Protein/*deficiency/genetics ; Animals ; Apoptosis/*drug effects ; CASP8 and FADD-Like Apoptosis Regulating Protein/metabolism ; Cell Proliferation/drug effects ; Colorectal Neoplasms/genetics/metabolism/*pathology/*prevention & control ; Gene Expression Regulation/drug effects ; Genes, APC ; Humans ; Intestinal Polyps/drug therapy/pathology ; Mice ; Mice, Inbred C57BL ; Precancerous Conditions/drug therapy/genetics/metabolism/pathology ; Proto-Oncogene Proteins c-myc/metabolism ; Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism ; Signal Transduction/drug effects ; Survival Rate ; TNF-Related Apoptosis-Inducing Ligand/administration & ; dosage/pharmacology/therapeutic use ; Time Factors ; Vitamin A/administration & dosage/*analogs & derivatives/pharmacology/therapeutic ; use ; beta Catenin/metabolism
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  • 77
    Publication Date: 2010-10-26
    Description: The energy-coupling factor (ECF) transporters, responsible for vitamin uptake in prokaryotes, are a unique family of membrane transporters. Each ECF transporter contains a membrane-embedded, substrate-binding protein (known as the S component), an energy-coupling module that comprises two ATP-binding proteins (known as the A and A' components) and a transmembrane protein (known as the T component). The structure and transport mechanism of the ECF family remain unknown. Here we report the crystal structure of RibU, the S component of the ECF-type riboflavin transporter from Staphylococcus aureus at 3.6-A resolution. RibU contains six transmembrane segments, adopts a previously unreported transporter fold and contains a riboflavin molecule bound to the L1 loop and the periplasmic portion of transmembrane segments 4-6. Structural analysis reveals the essential ligand-binding residues, identifies the putative transport path and, with sequence alignment, uncovers conserved structural features and suggests potential mechanisms of action among the ECF transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Peng -- Wang, Jiawei -- Shi, Yigong -- R01 GM084964/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Dec 2;468(7324):717-20. doi: 10.1038/nature09488. Epub 2010 Oct 24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, New Jersey 08544, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20972419" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Binding Sites ; Conserved Sequence ; Crystallography, X-Ray ; Ligands ; Membrane Transport Proteins/*chemistry/classification/*metabolism ; Models, Molecular ; Movement ; Periplasm/metabolism ; Protein Folding ; Protein Structure, Tertiary ; Riboflavin/chemistry/*metabolism ; Sequence Alignment ; Staphylococcus aureus/*chemistry ; Substrate Specificity
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  • 78
    Publication Date: 2010-10-01
    Description: Semaphorins and their receptor plexins constitute a pleiotropic cell-signalling system that is used in a wide variety of biological processes, and both protein families have been implicated in numerous human diseases. The binding of soluble or membrane-anchored semaphorins to the membrane-distal region of the plexin ectodomain activates plexin's intrinsic GTPase-activating protein (GAP) at the cytoplasmic region, ultimately modulating cellular adhesion behaviour. However, the structural mechanism underlying the receptor activation remains largely unknown. Here we report the crystal structures of the semaphorin 6A (Sema6A) receptor-binding fragment and the plexin A2 (PlxnA2) ligand-binding fragment in both their pre-signalling (that is, before binding) and signalling (after complex formation) states. Before binding, the Sema6A ectodomain was in the expected 'face-to-face' homodimer arrangement, similar to that adopted by Sema3A and Sema4D, whereas PlxnA2 was in an unexpected 'head-on' homodimer arrangement. In contrast, the structure of the Sema6A-PlxnA2 signalling complex revealed a 2:2 heterotetramer in which the two PlxnA2 monomers dissociated from one another and docked onto the top face of the Sema6A homodimer using the same interface as the head-on homodimer, indicating that plexins undergo 'partner exchange'. Cell-based activity measurements using mutant ligands/receptors confirmed that the Sema6A face-to-face dimer arrangement is physiologically relevant and is maintained throughout signalling events. Thus, homodimer-to-heterodimer transitions of cell-surface plexin that result in a specific orientation of its molecular axis relative to the membrane may constitute the structural mechanism by which the ligand-binding 'signal' is transmitted to the cytoplasmic region, inducing GAP domain rearrangements and activation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nogi, Terukazu -- Yasui, Norihisa -- Mihara, Emiko -- Matsunaga, Yukiko -- Noda, Masanori -- Yamashita, Naoya -- Toyofuku, Toshihiko -- Uchiyama, Susumu -- Goshima, Yoshio -- Kumanogoh, Atsushi -- Takagi, Junichi -- England -- Nature. 2010 Oct 28;467(7319):1123-7. doi: 10.1038/nature09473. Epub 2010 Sep 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20881961" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Crystallography, X-Ray ; HEK293 Cells ; Humans ; Ligands ; Mice ; Models, Molecular ; Molecular Sequence Data ; Nerve Tissue Proteins/*chemistry/genetics/*metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Cell Surface/*chemistry/genetics/*metabolism ; Semaphorins/*chemistry/genetics/*metabolism ; *Signal Transduction ; Structure-Activity Relationship
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  • 79
    Publication Date: 2010-08-21
    Description: Propionyl-coenzyme A carboxylase (PCC), a mitochondrial biotin-dependent enzyme, is essential for the catabolism of the amino acids Thr, Val, Ile and Met, cholesterol and fatty acids with an odd number of carbon atoms. Deficiencies in PCC activity in humans are linked to the disease propionic acidaemia, an autosomal recessive disorder that can be fatal in infants. The holoenzyme of PCC is an alpha(6)beta(6) dodecamer, with a molecular mass of 750 kDa. The alpha-subunit contains the biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) domains, whereas the beta-subunit supplies the carboxyltransferase (CT) activity. Here we report the crystal structure at 3.2-A resolution of a bacterial PCC alpha(6)beta(6) holoenzyme as well as cryo-electron microscopy (cryo-EM) reconstruction at 15-A resolution demonstrating a similar structure for human PCC. The structure defines the overall architecture of PCC and reveals unexpectedly that the alpha-subunits are arranged as monomers in the holoenzyme, decorating a central beta(6) hexamer. A hitherto unrecognized domain in the alpha-subunit, formed by residues between the BC and BCCP domains, is crucial for interactions with the beta-subunit. We have named it the BT domain. The structure reveals for the first time the relative positions of the BC and CT active sites in the holoenzyme. They are separated by approximately 55 A, indicating that the entire BCCP domain must translocate during catalysis. The BCCP domain is located in the active site of the beta-subunit in the current structure, providing insight for its involvement in the CT reaction. The structural information establishes a molecular basis for understanding the large collection of disease-causing mutations in PCC and is relevant for the holoenzymes of other biotin-dependent carboxylases, including 3-methylcrotonyl-CoA carboxylase (MCC) and eukaryotic acetyl-CoA carboxylase (ACC).〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2925307/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2925307/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Huang, Christine S -- Sadre-Bazzaz, Kianoush -- Shen, Yang -- Deng, Binbin -- Zhou, Z Hong -- Tong, Liang -- AI069015/AI/NIAID NIH HHS/ -- DK067238/DK/NIDDK NIH HHS/ -- GM071940/GM/NIGMS NIH HHS/ -- GM08281/GM/NIGMS NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 AI069015/AI/NIAID NIH HHS/ -- R01 AI069015-04/AI/NIAID NIH HHS/ -- R01 DK067238/DK/NIDDK NIH HHS/ -- R01 DK067238-07/DK/NIDDK NIH HHS/ -- R01 GM071940/GM/NIGMS NIH HHS/ -- R01 GM071940-05/GM/NIGMS NIH HHS/ -- T32 GM008281/GM/NIGMS NIH HHS/ -- T32 GM008281-23/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Aug 19;466(7309):1001-5. doi: 10.1038/nature09302.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Columbia University, New York, New York 10027, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20725044" target="_blank"〉PubMed〈/a〉
    Keywords: Acetyl-CoA Carboxylase/chemistry/metabolism/ultrastructure ; Biocatalysis ; Biotin/metabolism ; Carbon-Nitrogen Ligases/chemistry/metabolism/ultrastructure ; Carrier Proteins/chemistry/metabolism/ultrastructure ; Catalytic Domain ; *Cryoelectron Microscopy ; Crystallography, X-Ray ; Fatty Acid Synthase, Type II ; Holoenzymes/*chemistry/genetics/metabolism/*ultrastructure ; Humans ; Methylmalonyl-CoA Decarboxylase/*chemistry/genetics/metabolism/*ultrastructure ; Models, Molecular ; Mutation/genetics ; Propionic Acidemia/enzymology/genetics ; Protein Binding ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Protein Subunits/chemistry/metabolism ; Rhodobacteraceae/enzymology ; Structure-Activity Relationship
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  • 80
    Publication Date: 2010-05-14
    Description: Neurotransmitter:Na(+) symporters (NSS) remove neurotransmitters from the synapse in a reuptake process that is driven by the Na(+) gradient. Drugs that interfere with this reuptake mechanism, such as cocaine and antidepressants, profoundly influence behaviour and mood. To probe the nature of the conformational changes that are associated with substrate binding and transport, we have developed a single-molecule fluorescence imaging assay and combined it with functional and computational studies of the prokaryotic NSS homologue LeuT. Here we show molecular details of the modulation of intracellular gating of LeuT by substrates and inhibitors, as well as by mutations that alter binding, transport or both. Our direct observations of single-molecule transitions, reflecting structural dynamics of the intracellular region of the transporter that might be masked by ensemble averaging or suppressed under crystallographic conditions, are interpreted in the context of an allosteric mechanism that couples ion and substrate binding to transport.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2940119/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2940119/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhao, Yongfang -- Terry, Daniel -- Shi, Lei -- Weinstein, Harel -- Blanchard, Scott C -- Javitch, Jonathan A -- DA022413/DA/NIDA NIH HHS/ -- DA023694/DA/NIDA NIH HHS/ -- DA12408/DA/NIDA NIH HHS/ -- DA17293/DA/NIDA NIH HHS/ -- K05 DA022413/DA/NIDA NIH HHS/ -- K99 DA023694/DA/NIDA NIH HHS/ -- K99 DA023694-02/DA/NIDA NIH HHS/ -- R01 DA017293/DA/NIDA NIH HHS/ -- England -- Nature. 2010 May 13;465(7295):188-93. doi: 10.1038/nature09057.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Molecular Recognition, Columbia University College of Physicians and Surgeons, 630 W. 168th, New York, New York 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463731" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine/metabolism ; Allosteric Regulation ; Aquifoliaceae/*chemistry ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Crystallography, X-Ray ; Cysteine/chemistry/metabolism ; Escherichia coli ; Fluorescence Resonance Energy Transfer ; Leucine/metabolism ; Models, Molecular ; Molecular Dynamics Simulation ; Plasma Membrane Neurotransmitter Transport ; Proteins/*chemistry/genetics/*metabolism ; Protein Conformation ; Sodium/metabolism
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  • 81
    Publication Date: 2010-04-30
    Description: Dynamin is an atypical GTPase that catalyses membrane fission during clathrin-mediated endocytosis. The mechanisms of dynamin's basal and assembly-stimulated GTP hydrolysis are unknown, though both are indirectly influenced by the GTPase effector domain (GED). Here we present the 2.0 A resolution crystal structure of a human dynamin 1-derived minimal GTPase-GED fusion protein, which was dimeric in the presence of the transition state mimic GDP.AlF(4)(-).The structure reveals dynamin's catalytic machinery and explains how assembly-stimulated GTP hydrolysis is achieved through G domain dimerization. A sodium ion present in the active site suggests that dynamin uses a cation to compensate for the developing negative charge in the transition state in the absence of an arginine finger. Structural comparison to the rat dynamin G domain reveals key conformational changes that promote G domain dimerization and stimulated hydrolysis. The structure of the GTPase-GED fusion protein dimer provides insight into the mechanisms underlying dynamin-catalysed membrane fission.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879890/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879890/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chappie, Joshua S -- Acharya, Sharmistha -- Leonard, Marilyn -- Schmid, Sandra L -- Dyda, Fred -- F31 MH081419/MH/NIMH NIH HHS/ -- F31 MH081419-02/MH/NIMH NIH HHS/ -- GM42455/GM/NIGMS NIH HHS/ -- MH081419/MH/NIMH NIH HHS/ -- MH61345/MH/NIMH NIH HHS/ -- R01 GM042455/GM/NIGMS NIH HHS/ -- R01 GM042455-20/GM/NIGMS NIH HHS/ -- R37 MH061345/MH/NIMH NIH HHS/ -- R37 MH061345-10/MH/NIMH NIH HHS/ -- Intramural NIH HHS/ -- England -- Nature. 2010 May 27;465(7297):435-40. doi: 10.1038/nature09032. Epub 2010 Apr 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland 20892, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20428113" target="_blank"〉PubMed〈/a〉
    Keywords: Aluminum Compounds/metabolism ; Amino Acid Sequence ; Biocatalysis ; Catalytic Domain/genetics ; Conserved Sequence ; Crystallography, X-Ray ; Dynamin I/*chemistry/genetics/*metabolism ; Enzyme Activation ; Fluorides/metabolism ; GTP Phosphohydrolases/*chemistry/genetics/*metabolism ; Guanosine Diphosphate/analogs & derivatives/metabolism ; Humans ; Hydrolysis ; Models, Molecular ; *Protein Multimerization ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Sodium/metabolism
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  • 82
    Publication Date: 2010-07-27
    Description: One of the detrimental effects of ultraviolet radiation on DNA is the formation of the (6-4) photoproduct, 6-4PP, between two adjacent pyrimidine rings. This lesion interferes with replication and transcription, and may result in mutation and cell death. In many organisms, a flavoenzyme called photolyase uses blue light energy to repair the 6-4PP (ref. 3). The molecular mechanism of the repair reaction is poorly understood. Here, we use ultrafast spectroscopy to show that the key step in the repair photocycle is acyclic proton transfer between the enzyme and the substrate. By femtosecond synchronization of the enzymatic dynamics with the repair function, we followed the function evolution and observed direct electron transfer from the excited flavin cofactor to the 6-4PP in 225 picoseconds, but surprisingly fast back electron transfer in 50 picoseconds without repair. We found that the catalytic proton transfer between a histidine residue in the active site and the 6-4PP, induced by the initial photoinduced electron transfer from the excited flavin cofactor to 6-4PP, occurs in 425 picoseconds and leads to 6-4PP repair in tens of nanoseconds. These key dynamics define the repair photocycle and explain the underlying molecular mechanism of the enzyme's modest efficiency.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018752/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018752/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Jiang -- Liu, Zheyun -- Tan, Chuang -- Guo, Xunmin -- Wang, Lijuan -- Sancar, Aziz -- Zhong, Dongping -- GM074813/GM/NIGMS NIH HHS/ -- P30 ES010126/ES/NIEHS NIH HHS/ -- R01 GM031082/GM/NIGMS NIH HHS/ -- R01 GM074813/GM/NIGMS NIH HHS/ -- R01 GM074813-04/GM/NIGMS NIH HHS/ -- R01 HG002779-05/HG/NHGRI NIH HHS/ -- R01 HG002779-06/HG/NHGRI NIH HHS/ -- R01 LM006845/LM/NLM NIH HHS/ -- England -- Nature. 2010 Aug 12;466(7308):887-890. doi: 10.1038/nature09192.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Program of Biophysics, The Ohio State University, Columbus, Ohio 43210, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20657578" target="_blank"〉PubMed〈/a〉
    Keywords: Absorption ; Animals ; Arabidopsis/*enzymology/genetics ; Biocatalysis ; DNA Damage ; *DNA Repair/radiation effects ; Deoxyribodipyrimidine Photo-Lyase/chemistry/genetics/*metabolism ; Drosophila melanogaster/enzymology ; Electrons ; Flavins/chemistry/metabolism ; Histidine/genetics/metabolism ; Kinetics ; Models, Molecular ; Protons ; Pyrimidine Dimers/chemistry/*metabolism/*radiation effects ; Time Factors ; *Ultraviolet Rays
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  • 83
    Publication Date: 2010-06-11
    Description: Lymphocytes and neutrophils are rapidly depleted by systemic infection. Progenitor cells of the haematopoietic system, such as common myeloid progenitors and common lymphoid progenitors, increase the production of immune cells to restore and maintain homeostasis during chronic infection, but the contribution of haematopoietic stem cells (HSCs) to this process is largely unknown. Here we show, using an in vivo mouse model of Mycobacterium avium infection, that an increased proportion of long-term repopulating HSCs proliferate during M. avium infection, and that this response requires interferon-gamma (IFN-gamma) but not interferon-alpha (IFN-alpha) signalling. Thus, the haematopoietic response to chronic bacterial infection involves the activation not only of intermediate blood progenitors but of long-term repopulating HSCs as well. IFN-gamma is sufficient to promote long-term repopulating HSC proliferation in vivo; furthermore, HSCs from IFN-gamma-deficient mice have a lower proliferative rate, indicating that baseline IFN-gamma tone regulates HSC activity. These findings implicate IFN-gamma both as a regulator of HSCs during homeostasis and under conditions of infectious stress. Our studies contribute to a deeper understanding of haematological responses in patients with chronic infections such as HIV/AIDS or tuberculosis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935898/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935898/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Baldridge, Megan T -- King, Katherine Y -- Boles, Nathan C -- Weksberg, David C -- Goodell, Margaret A -- K08 HL098898/HL/NHLBI NIH HHS/ -- P50 CA126752/CA/NCI NIH HHS/ -- P50 CA126752-030005/CA/NCI NIH HHS/ -- R01 DK058192/DK/NIDDK NIH HHS/ -- R01 DK058192-10/DK/NIDDK NIH HHS/ -- R01 EB005173/EB/NIBIB NIH HHS/ -- R01 EB005173-05/EB/NIBIB NIH HHS/ -- R01 HL096360/HL/NHLBI NIH HHS/ -- T32 HL092332/HL/NHLBI NIH HHS/ -- T32 HL092332-07/HL/NHLBI NIH HHS/ -- U54 HL081007-05/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Jun 10;465(7299):793-7. doi: 10.1038/nature09135.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20535209" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bone Marrow Transplantation ; Cell Count ; Cell Proliferation ; Chronic Disease ; Hematopoietic Stem Cells/*cytology/*immunology ; Homeostasis/*immunology/physiology ; Interferon-alpha ; Interferon-gamma/deficiency/*immunology/*metabolism ; Mice ; Mice, Inbred C57BL ; Multipotent Stem Cells/cytology/immunology ; Mycobacterium avium/immunology ; Signal Transduction ; Tuberculosis/blood/*immunology/microbiology
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  • 84
    Publication Date: 2010-05-14
    Description: Phosphorylated derivatives of phosphatidylinositol, collectively referred to as phosphoinositides, occur in the cytoplasmic leaflet of cellular membranes and regulate activities such as vesicle transport, cytoskeletal reorganization and signal transduction. Recent studies have indicated an important role for phosphoinositide metabolism in the aetiology of diseases such as cancer, diabetes, myopathy and inflammation. Although the biological functions of the phosphatases that regulate phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) have been well characterized, little is known about the functions of the phosphatases regulating the closely related molecule phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P(2)). Here we show that inositol polyphosphate phosphatase 4A (INPP4A), a PtdIns(3,4)P(2) phosphatase, is a suppressor of glutamate excitotoxicity in the central nervous system. Targeted disruption of the Inpp4a gene in mice leads to neurodegeneration in the striatum, the input nucleus of the basal ganglia that has a central role in motor and cognitive behaviours. Notably, Inpp4a(-/-) mice show severe involuntary movement disorders. In vitro, Inpp4a gene silencing via short hairpin RNA renders cultured primary striatal neurons vulnerable to cell death mediated by N-methyl-d-aspartate-type glutamate receptors (NMDARs). Mechanistically, INPP4A is found at the postsynaptic density and regulates synaptic NMDAR localization and NMDAR-mediated excitatory postsynaptic current. Thus, INPP4A protects neurons from excitotoxic cell death and thereby maintains the functional integrity of the brain. Our study demonstrates that PtdIns(3,4)P(2), PtdIns(3,4,5)P(3) and the phosphatases acting on them can have distinct regulatory roles, and provides insight into the unique aspects and physiological significance of PtdIns(3,4)P(2) metabolism. INPP4A represents, to our knowledge, the first signalling protein with a function in neurons to suppress excitotoxic cell death. The discovery of a direct link between PtdIns(3,4)P(2) metabolism and the regulation of neurodegeneration and involuntary movements may aid the development of new approaches for the treatment of neurodegenerative disorders.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sasaki, Junko -- Kofuji, Satoshi -- Itoh, Reietsu -- Momiyama, Toshihiko -- Takayama, Kiyohiko -- Murakami, Haruka -- Chida, Shinsuke -- Tsuya, Yuko -- Takasuga, Shunsuke -- Eguchi, Satoshi -- Asanuma, Ken -- Horie, Yasuo -- Miura, Kouichi -- Davies, Elizabeth Michele -- Mitchell, Christina -- Yamazaki, Masakazu -- Hirai, Hirokazu -- Takenawa, Tadaomi -- Suzuki, Akira -- Sasaki, Takehiko -- England -- Nature. 2010 May 27;465(7297):497-501. doi: 10.1038/nature09023. Epub 2010 May 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medical Biology, Akita University Graduate School of Medicine, Akita 010-8543, Japan. sasakij@med.akita-u.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20463662" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Death/drug effects ; Cell Survival ; Cells, Cultured ; Down-Regulation ; Dyskinesias/genetics/pathology/physiopathology ; Glutamic Acid/metabolism/pharmacology/*toxicity ; Humans ; Mice ; Mice, Inbred C57BL ; Neostriatum/drug effects/metabolism/pathology ; Neurodegenerative Diseases/genetics/pathology/physiopathology ; Neurons/*cytology/*drug effects/enzymology/pathology ; Phosphoric Monoester Hydrolases/deficiency/genetics/*metabolism ; Receptors, N-Methyl-D-Aspartate/metabolism ; Survival Rate ; Synapses/metabolism ; Weight Loss
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  • 85
    Publication Date: 2010-11-26
    Description: Tumorigenesis is a multistep process that results from the sequential accumulation of mutations in key oncogene and tumour suppressor pathways. Personalized cancer therapy that is based on targeting these underlying genetic abnormalities presupposes that sustained inactivation of tumour suppressors and activation of oncogenes is essential in advanced cancers. Mutations in the p53 tumour-suppressor pathway are common in human cancer and significant efforts towards pharmaceutical reactivation of defective p53 pathways are underway. Here we show that restoration of p53 in established murine lung tumours leads to significant but incomplete tumour cell loss specifically in malignant adenocarcinomas, but not in adenomas. We define amplification of MAPK signalling as a critical determinant of malignant progression and also a stimulator of Arf tumour-suppressor expression. The response to p53 restoration in this context is critically dependent on the expression of Arf. We propose that p53 not only limits malignant progression by suppressing the acquisition of alterations that lead to tumour progression, but also, in the context of p53 restoration, responds to increased oncogenic signalling to mediate tumour regression. Our observations also underscore that the p53 pathway is not engaged by low levels of oncogene activity that are sufficient for early stages of lung tumour development. These data suggest that restoration of pathways important in tumour progression, as opposed to initiation, may lead to incomplete tumour regression due to the stage-heterogeneity of tumour cell populations.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003305/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003305/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Feldser, David M -- Kostova, Kamena K -- Winslow, Monte M -- Taylor, Sarah E -- Cashman, Chris -- Whittaker, Charles A -- Sanchez-Rivera, Francisco J -- Resnick, Rebecca -- Bronson, Roderick -- Hemann, Michael T -- Jacks, Tyler -- P30 CA014051/CA/NCI NIH HHS/ -- P30 CA014051-37/CA/NCI NIH HHS/ -- P30 CA014051-38/CA/NCI NIH HHS/ -- P30 CA014051-39/CA/NCI NIH HHS/ -- P30 CA014051-40/CA/NCI NIH HHS/ -- P30-CA14051/CA/NCI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Nov 25;468(7323):572-5. doi: 10.1038/nature09535.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Koch Institute for Integrative Cancer Research, Department of Biology, and Howard Hughes Medical Institute, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21107428" target="_blank"〉PubMed〈/a〉
    Keywords: Adenocarcinoma/metabolism/*physiopathology ; Adenoma/metabolism/*physiopathology ; Animals ; Cell Proliferation ; *Disease Progression ; Lung Neoplasms/*physiopathology ; Mice ; Mice, Inbred C57BL ; Mitogen-Activated Protein Kinases/metabolism ; Signal Transduction ; Tumor Suppressor Protein p53/genetics/*metabolism
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  • 86
    Publication Date: 2010-12-03
    Description: Alphaviruses are enveloped RNA viruses that have a diameter of about 700 A and can be lethal human pathogens. Entry of virus into host cells by endocytosis is controlled by two envelope glycoproteins, E1 and E2. The E2-E1 heterodimers form 80 trimeric spikes on the icosahedral virus surface, 60 with quasi-three-fold symmetry and 20 coincident with the icosahedral three-fold axes arranged with T = 4 quasi-symmetry. The E1 glycoprotein has a hydrophobic fusion loop at one end and is responsible for membrane fusion. The E2 protein is responsible for receptor binding and protects the fusion loop at neutral pH. The lower pH in the endosome induces the virions to undergo an irreversible conformational change in which E2 and E1 dissociate and E1 forms homotrimers, triggering fusion of the viral membrane with the endosomal membrane and then releasing the viral genome into the cytoplasm. Here we report the structure of an alphavirus spike, crystallized at low pH, representing an intermediate in the fusion process and clarifying the maturation process. The trimer of E2-E1 in the crystal structure is similar to the spikes in the neutral pH virus except that the E2 middle region is disordered, exposing the fusion loop. The amino- and carboxy-terminal domains of E2 each form immunoglobulin-like folds, consistent with the receptor attachment properties of E2.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057476/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057476/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Long -- Jose, Joyce -- Xiang, Ye -- Kuhn, Richard J -- Rossmann, Michael G -- P01 AI055672/AI/NIAID NIH HHS/ -- P01 AI055672-07/AI/NIAID NIH HHS/ -- England -- Nature. 2010 Dec 2;468(7324):705-8. doi: 10.1038/nature09546.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, Indiana 47907-2054, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21124457" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Cryoelectron Microscopy ; Crystallography, X-Ray ; Drosophila melanogaster ; Endosomes/metabolism ; Hydrogen-Ion Concentration ; Hydrophobic and Hydrophilic Interactions ; Membrane Fusion ; Membrane Glycoproteins/chemistry/metabolism ; Models, Molecular ; Protein Multimerization ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Receptors, Virus/metabolism ; Sindbis Virus/*chemistry/*metabolism ; Viral Envelope Proteins/*chemistry/*metabolism ; Viral Fusion Proteins/chemistry/metabolism ; Virion/chemistry/metabolism ; *Virus Internalization
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  • 87
    Publication Date: 2010-05-07
    Description: The formation and guidance of specialized endothelial tip cells is essential for both developmental and pathological angiogenesis. Notch-1 signalling regulates the generation of tip cells, which respond to gradients of vascular endothelial growth factor (VEGF-A). The molecular cues and signalling pathways that control the guidance of tip cells are poorly understood. Bidirectional signalling by Eph receptors and ephrin ligands represents one of the most important guidance cues involved in axon path finding. Here we show that ephrin-B2 reverse signalling involving PDZ interactions regulates endothelial tip cell guidance to control angiogenic sprouting and branching in physiological and pathological angiogenesis. In vivo, ephrin-B2 PDZ-signalling-deficient mice (ephrin-B2DeltaV) exhibit a reduced number of tip cells with fewer filopodial extensions at the vascular front in the mouse retina. In pathological settings, impaired PDZ signalling decreases tumour vascularization and growth. Mechanistically, we show that ephrin-B2 controls VEGF receptor (VEGFR)-2 internalization and signalling. Importantly, internalization of VEGFR2 is necessary for activation and downstream signalling of the receptor and is required for VEGF-induced tip cell filopodial extension. Together, our results suggest that ephrin-B2 at the tip cell filopodia regulates the proper spatial activation of VEGFR2 endocytosis and signalling to direct filopodial extension. Blocking ephrin-B2 reverse signalling may be an attractive alternative or combinatorial anti-angiogenic therapy strategy to disrupt VEGFR2 function in tumour angiogenesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sawamiphak, Suphansa -- Seidel, Sascha -- Essmann, Clara L -- Wilkinson, George A -- Pitulescu, Mara E -- Acker, Till -- Acker-Palmer, Amparo -- England -- Nature. 2010 May 27;465(7297):487-91. doi: 10.1038/nature08995. Epub 2010 May 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Frankfurt Institute for Molecular Life Sciences and Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20445540" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astrocytoma/*blood supply/*metabolism/pathology ; Brain/blood supply ; Cells, Cultured ; Endocytosis ; Endothelial Cells/cytology/metabolism ; Ephrin-B2/deficiency/genetics/*metabolism ; Mice ; Mice, Inbred C57BL ; Neoplasm Transplantation ; *Neovascularization, Pathologic ; Neovascularization, Physiologic ; Pseudopodia/metabolism ; Retina ; Retinal Vessels/cytology/physiology ; Signal Transduction ; Vascular Endothelial Growth Factor Receptor-2/*metabolism
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  • 88
    Publication Date: 2010-03-30
    Description: Most archaeal groups and deeply branching bacterial lineages harbour thermophilic organisms with a chemolithoautotrophic metabolism. They live at high temperatures in volcanic habitats at the expense of inorganic substances, often under anoxic conditions. These autotrophic organisms use diverse carbon dioxide fixation mechanisms generating acetyl-coenzyme A, from which gluconeogenesis must start. Here we show that virtually all archaeal groups as well as the deeply branching bacterial lineages contain a bifunctional fructose 1,6-bisphosphate (FBP) aldolase/phosphatase with both FBP aldolase and FBP phosphatase activity. This enzyme is missing in most other Bacteria and in Eukaryota, and is heat-stabile even in mesophilic marine Crenarchaeota. Its bifunctionality ensures that heat-labile triosephosphates are quickly removed and trapped in stabile fructose 6-phosphate, rendering gluconeogenesis unidirectional. We propose that this highly conserved, heat-stabile and bifunctional FBP aldolase/phosphatase represents the pace-making ancestral gluconeogenic enzyme, and that in evolution gluconeogenesis preceded glycolysis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Say, Rafael F -- Fuchs, Georg -- England -- Nature. 2010 Apr 15;464(7291):1077-81. doi: 10.1038/nature08884. Epub 2010 Mar 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Mikrobiologie, Fakultat Biologie, Universitat Freiburg, Schanzlestrasse 1, D-79104 Freiburg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20348906" target="_blank"〉PubMed〈/a〉
    Keywords: Archaea/enzymology ; Bacteria/enzymology ; Biocatalysis ; Catalytic Domain ; Enzyme Stability ; *Evolution, Molecular ; Fructose-Bisphosphate Aldolase/chemistry/*metabolism ; Fructosediphosphates/chemistry/*metabolism ; Fructosephosphates/metabolism ; *Gluconeogenesis ; Glycolysis ; Hot Temperature ; Models, Molecular ; Origin of Life ; Phosphoric Monoester Hydrolases/chemistry/*metabolism ; Phylogeny ; Protein Conformation ; Ribosomal Proteins/classification
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  • 89
    Publication Date: 2010-04-07
    Description: Targeting of proteins to appropriate subcellular compartments is a crucial process in all living cells. Secretory and membrane proteins usually contain an amino-terminal signal peptide, which is recognized by the signal recognition particle (SRP) when nascent polypeptide chains emerge from the ribosome. The SRP-ribosome nascent chain complex is then targeted through its GTP-dependent interaction with SRP receptor to the protein-conducting channel on endoplasmic reticulum membrane in eukaryotes or plasma membrane in bacteria. A universally conserved component of SRP (refs 1, 2), SRP54 or its bacterial homologue, fifty-four homologue (Ffh), binds the signal peptides, which have a highly divergent sequence divisible into a positively charged n-region, an h-region commonly containing 8-20 hydrophobic residues and a polar c-region. No structure has been reported that exemplifies SRP54 binding of any signal sequence. Here we have produced a fusion protein between Sulfolobus solfataricus SRP54 (Ffh) and a signal peptide connected via a flexible linker. This fusion protein oligomerizes in solution through interaction between the SRP54 and signal peptide moieties belonging to different chains, and it is functional, as demonstrated by its ability to bind SRP RNA and SRP receptor FtsY. We present the crystal structure at 3.5 A resolution of an SRP54-signal peptide complex in the dimer, which reveals how a signal sequence is recognized by SRP54.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897128/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897128/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Janda, Claudia Y -- Li, Jade -- Oubridge, Chris -- Hernandez, Helena -- Robinson, Carol V -- Nagai, Kiyoshi -- MC_U105184330/Medical Research Council/United Kingdom -- U.1051.04.016(78933)/Medical Research Council/United Kingdom -- Medical Research Council/United Kingdom -- England -- Nature. 2010 May 27;465(7297):507-10. doi: 10.1038/nature08870. Epub 2010 Apr 4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20364120" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/metabolism ; Crystallography, X-Ray ; Mass Spectrometry ; Models, Molecular ; Molecular Sequence Data ; Protein Binding ; Protein Multimerization ; Protein Sorting Signals/*physiology ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Receptors, Cytoplasmic and Nuclear/metabolism ; Receptors, Virus/metabolism ; Recombinant Fusion Proteins/chemistry/metabolism ; Signal Recognition Particle/*chemistry/*metabolism ; Structure-Activity Relationship ; Sulfolobus solfataricus/*chemistry
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  • 90
    Publication Date: 2010-01-08
    Description: The life cycle of mammals begins when a sperm enters an egg. Immediately after fertilization, both the maternal and paternal genomes undergo dramatic reprogramming to prepare for the transition from germ cell to somatic cell transcription programs. One of the molecular events that takes place during this transition is the demethylation of the paternal genome. Despite extensive efforts, the factors responsible for paternal DNA demethylation have not been identified. To search for such factors, we developed a live cell imaging system that allows us to monitor the paternal DNA methylation state in zygotes. Through short-interfering-RNA-mediated knockdown in mouse zygotes, we identified Elp3 (also called KAT9), a component of the elongator complex, to be important for paternal DNA demethylation. We demonstrate that knockdown of Elp3 impairs paternal DNA demethylation as indicated by reporter binding, immunostaining and bisulphite sequencing. Similar results were also obtained when other elongator components, Elp1 and Elp4, were knocked down. Importantly, injection of messenger RNA encoding the Elp3 radical SAM domain mutant, but not the HAT domain mutant, into MII oocytes before fertilization also impaired paternal DNA demethylation, indicating that the SAM radical domain is involved in the demethylation process. Our study not only establishes a critical role for the elongator complex in zygotic paternal genome demethylation, but also indicates that the demethylation process may be mediated through a reaction that requires an intact radical SAM domain.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834414/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834414/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Okada, Yuki -- Yamagata, Kazuo -- Hong, Kwonho -- Wakayama, Teruhiko -- Zhang, Yi -- R01 GM068804/GM/NIGMS NIH HHS/ -- R01 GM068804-07/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Jan 28;463(7280):554-8. doi: 10.1038/nature08732. Epub 2010 Jan 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Chapel Hill, North Carolina 27599-7295, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20054296" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Cells, Cultured ; *DNA Methylation ; Embryonic Development/*genetics ; Female ; Gene Knockdown Techniques ; Genome/*genetics ; Histone Acetyltransferases/*metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mutation/genetics ; Protein Structure, Tertiary/genetics ; Zygote/*metabolism
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  • 91
    Publication Date: 2010-09-17
    Description: F-actin is a helical assembly of actin, which is a component of muscle fibres essential for contraction and has a crucial role in numerous cellular processes, such as the formation of lamellipodia and filopodia, as the most abundant component and regulator of cytoskeletons by dynamic assembly and disassembly (from G-actin to F-actin and vice versa). Actin is a ubiquitous protein and is involved in important biological functions, but the definitive high-resolution structure of F-actin remains unknown. Although a recent atomic model well reproduced X-ray fibre diffraction intensity data from a highly oriented liquid-crystalline sol specimen, its refinement without experimental phase information has certain limitations. Direct visualization of the structure by electron cryomicroscopy, however, has been difficult because it is relatively thin and flexible. Here we report the F-actin structure at 6.6 A resolution, made obtainable by recent advances in electron cryomicroscopy. The density map clearly resolves all the secondary structures of G-actin, such as alpha-helices, beta-structures and loops, and makes unambiguous modelling and refinement possible. Complex domain motions that open the nucleotide-binding pocket on F-actin formation, specific D-loop and terminal conformations, and relatively tight axial but markedly loose interprotofilament interactions hydrophilic in nature are revealed in the F-actin model, and all seem to be important for dynamic functions of actin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fujii, Takashi -- Iwane, Atsuko H -- Yanagida, Toshio -- Namba, Keiichi -- England -- Nature. 2010 Oct 7;467(7316):724-8. doi: 10.1038/nature09372. Epub 2010 Sep 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20844487" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*chemistry/*ultrastructure ; Animals ; *Cryoelectron Microscopy ; Crystallography, X-Ray ; Hydrogen Bonding ; Models, Molecular ; Protein Structure, Secondary ; Protein Subunits ; Rabbits ; Static Electricity
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  • 92
    Publication Date: 2010-12-24
    Description: Cancer is a disease consisting of both genetic and epigenetic changes. Although increasing evidence demonstrates that tumour progression entails chromatin-mediated changes such as DNA methylation, the role of histone variants in cancer initiation and progression currently remains unclear. Histone variants replace conventional histones within the nucleosome and confer unique biological functions to chromatin. Here we report that the histone variant macroH2A (mH2A) suppresses tumour progression of malignant melanoma. Loss of mH2A isoforms, histone variants generally associated with condensed chromatin and fine-tuning of developmental gene expression programs, is positively correlated with increasing malignant phenotype of melanoma cells in culture and human tissue samples. Knockdown of mH2A isoforms in melanoma cells of low malignancy results in significantly increased proliferation and migration in vitro and growth and metastasis in vivo. Restored expression of mH2A isoforms rescues these malignant phenotypes in vitro and in vivo. We demonstrate that the tumour-promoting function of mH2A loss is mediated, at least in part, through direct transcriptional upregulation of CDK8. Suppression of CDK8, a colorectal cancer oncogene, inhibits proliferation of melanoma cells, and knockdown of CDK8 in cells depleted of mH2A suppresses the proliferative advantage induced by mH2A loss. Moreover, a significant inverse correlation between mH2A and CDK8 expression levels exists in melanoma patient samples. Taken together, our results demonstrate that mH2A is a critical component of chromatin that suppresses the development of malignant melanoma, a highly intractable cutaneous neoplasm.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057940/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057940/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kapoor, Avnish -- Goldberg, Matthew S -- Cumberland, Lara K -- Ratnakumar, Kajan -- Segura, Miguel F -- Emanuel, Patrick O -- Menendez, Silvia -- Vardabasso, Chiara -- Leroy, Gary -- Vidal, Claudia I -- Polsky, David -- Osman, Iman -- Garcia, Benjamin A -- Hernando, Eva -- Bernstein, Emily -- 5P30CA016087-27/CA/NCI NIH HHS/ -- CA109388/CA/NCI NIH HHS/ -- R21 CA150117/CA/NCI NIH HHS/ -- R21 CA150117-01/CA/NCI NIH HHS/ -- R21 CA150117-02/CA/NCI NIH HHS/ -- R21CA150117/CA/NCI NIH HHS/ -- England -- Nature. 2010 Dec 23;468(7327):1105-9. doi: 10.1038/nature09590.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Oncological Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21179167" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Cyclin-Dependent Kinase 8/*metabolism ; Disease Progression ; Gene Expression Profiling ; *Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; HCT116 Cells ; Histones/deficiency/genetics/*metabolism ; Humans ; Melanoma/*pathology/physiopathology ; Melanoma, Experimental ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Neoplasm Metastasis/*pathology/physiopathology ; Rats ; Up-Regulation
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  • 93
    Publication Date: 2010-10-29
    Description: The plant SLAC1 anion channel controls turgor pressure in the aperture-defining guard cells of plant stomata, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought or high levels of carbon dioxide. Here we determine the crystal structure of a bacterial homologue (Haemophilus influenzae) of SLAC1 at 1.20 A resolution, and use structure-inspired mutagenesis to analyse the conductance properties of SLAC1 channels. SLAC1 is a symmetrical trimer composed from quasi-symmetrical subunits, each having ten transmembrane helices arranged from helical hairpin pairs to form a central five-helix transmembrane pore that is gated by an extremely conserved phenylalanine residue. Conformational features indicate a mechanism for control of gating by kinase activation, and electrostatic features of the pore coupled with electrophysiological characteristics indicate that selectivity among different anions is largely a function of the energetic cost of ion dehydration.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548404/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548404/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Yu-Hang -- Hu, Lei -- Punta, Marco -- Bruni, Renato -- Hillerich, Brandan -- Kloss, Brian -- Rost, Burkhard -- Love, James -- Siegelbaum, Steven A -- Hendrickson, Wayne A -- R01 GM034102/GM/NIGMS NIH HHS/ -- U54 GM075026/GM/NIGMS NIH HHS/ -- U54 GM095315/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Oct 28;467(7319):1074-80. doi: 10.1038/nature09487.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20981093" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Arabidopsis/genetics/metabolism ; Arabidopsis Proteins/*chemistry ; Bacterial Proteins/*chemistry/genetics/metabolism ; Crystallography, X-Ray ; Electric Conductivity ; Haemophilus influenzae/*chemistry/genetics ; Ion Channel Gating ; Membrane Proteins/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Oocytes/metabolism ; Phenylalanine/chemistry/metabolism ; Plant Stomata/*metabolism ; Static Electricity ; *Structural Homology, Protein ; Substrate Specificity ; Xenopus laevis
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  • 94
    Publication Date: 2010-07-09
    Description: The coupled interplay between activation and inactivation gating is a functional hallmark of K(+) channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well defined boundary of energetically coupled residues. The structure of the K(+) channel KcsA in its fully open conformation, in addition to four other partial channel openings, richly illustrates the structural basis of activation-inactivation gating. Here, we identify the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that, as a consequence of the hinge-bending and rotation of the TM2 helix, the aromatic ring of Phe 103 tilts towards residues Thr 74 and Thr 75 in the pore-helix and towards Ile 100 in the neighbouring subunit. This allows the network of hydrogen bonds among residues Trp 67, Glu 71 and Asp 80 to destabilize the selectivity filter, allowing entry to its non-conductive conformation. Mutations at position 103 have a size-dependent effect on gating kinetics: small side-chain substitutions F103A and F103C severely impair inactivation kinetics, whereas larger side chains such as F103W have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open-state interaction-energies between Phe 103 and the surrounding residues. We probed similar interactions in the Shaker K(+) channel where inactivation was impaired in the mutant I470A. We propose that side-chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K(+) channels.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033755/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033755/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuello, Luis G -- Jogini, Vishwanath -- Cortes, D Marien -- Pan, Albert C -- Gagnon, Dominique G -- Dalmas, Olivier -- Cordero-Morales, Julio F -- Chakrapani, Sudha -- Roux, Benoit -- Perozo, Eduardo -- R01 GM057846/GM/NIGMS NIH HHS/ -- R01 GM057846-15/GM/NIGMS NIH HHS/ -- R01 GM062342/GM/NIGMS NIH HHS/ -- R01 GM062342-05/GM/NIGMS NIH HHS/ -- R01-GM57846/GM/NIGMS NIH HHS/ -- R01-GM62342/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jul 8;466(7303):272-5. doi: 10.1038/nature09136.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20613845" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Cysteine/genetics/metabolism ; Electron Spin Resonance Spectroscopy ; Humans ; Hydrogen Bonding ; *Ion Channel Gating ; Kinetics ; Models, Molecular ; Molecular Dynamics Simulation ; Phenylalanine/metabolism ; Potassium Channels/*chemistry/genetics/*metabolism ; Protein Conformation ; Shaker Superfamily of Potassium Channels/chemistry/genetics/metabolism ; Streptomyces lividans/*chemistry ; Structure-Activity Relationship
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  • 95
    Publication Date: 2010-10-22
    Description: Accumulation of amyloid fibrils in the viscera and connective tissues causes systemic amyloidosis, which is responsible for about one in a thousand deaths in developed countries. Localized amyloid can also have serious consequences; for example, cerebral amyloid angiopathy is an important cause of haemorrhagic stroke. The clinical presentations of amyloidosis are extremely diverse and the diagnosis is rarely made before significant organ damage is present. There is therefore a major unmet need for therapy that safely promotes the clearance of established amyloid deposits. Over 20 different amyloid fibril proteins are responsible for different forms of clinically significant amyloidosis and treatments that substantially reduce the abundance of the respective amyloid fibril precursor proteins can arrest amyloid accumulation. Unfortunately, control of fibril-protein production is not possible in some forms of amyloidosis and in others it is often slow and hazardous. There is no therapy that directly targets amyloid deposits for enhanced clearance. However, all amyloid deposits contain the normal, non-fibrillar plasma glycoprotein, serum amyloid P component (SAP). Here we show that administration of anti-human-SAP antibodies to mice with amyloid deposits containing human SAP triggers a potent, complement-dependent, macrophage-derived giant cell reaction that swiftly removes massive visceral amyloid deposits without adverse effects. Anti-SAP-antibody treatment is clinically feasible because circulating human SAP can be depleted in patients by the bis-d-proline compound CPHPC, thereby enabling injected anti-SAP antibodies to reach residual SAP in the amyloid deposits. The unprecedented capacity of this novel combined therapy to eliminate amyloid deposits should be applicable to all forms of systemic and local amyloidosis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2975378/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2975378/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bodin, Karl -- Ellmerich, Stephan -- Kahan, Melvyn C -- Tennent, Glenys A -- Loesch, Andrzej -- Gilbertson, Janet A -- Hutchinson, Winston L -- Mangione, Palma P -- Gallimore, J Ruth -- Millar, David J -- Minogue, Shane -- Dhillon, Amar P -- Taylor, Graham W -- Bradwell, Arthur R -- Petrie, Aviva -- Gillmore, Julian D -- Bellotti, Vittorio -- Botto, Marina -- Hawkins, Philip N -- Pepys, Mark B -- G0800737/1/National Centre for the Replacement, Refinement and Reduction of Animals in Research/United Kingdom -- G0901596/Medical Research Council/United Kingdom -- G7900510/Medical Research Council/United Kingdom -- G7900510(69566)/Medical Research Council/United Kingdom -- G97900510/Medical Research Council/United Kingdom -- England -- Nature. 2010 Nov 4;468(7320):93-7. doi: 10.1038/nature09494. Epub 2010 Oct 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20962779" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/*drug effects ; Amyloidosis/*prevention & control/therapy ; Animals ; Antibodies/*immunology/*pharmacology/therapeutic use ; Disease Models, Animal ; Humans ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Serum Amyloid P-Component/*antagonists & inhibitors/genetics/*immunology
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  • 96
    Publication Date: 2010-08-06
    Description: Despite the success of genomics in identifying new essential bacterial genes, there is a lack of sustainable leads in antibacterial drug discovery to address increasing multidrug resistance. Type IIA topoisomerases cleave and religate DNA to regulate DNA topology and are a major class of antibacterial and anticancer drug targets, yet there is no well developed structural basis for understanding drug action. Here we report the 2.1 A crystal structure of a potent, new class, broad-spectrum antibacterial agent in complex with Staphylococcus aureus DNA gyrase and DNA, showing a new mode of inhibition that circumvents fluoroquinolone resistance in this clinically important drug target. The inhibitor 'bridges' the DNA and a transient non-catalytic pocket on the two-fold axis at the GyrA dimer interface, and is close to the active sites and fluoroquinolone binding sites. In the inhibitor complex the active site seems poised to cleave the DNA, with a single metal ion observed between the TOPRIM (topoisomerase/primase) domain and the scissile phosphate. This work provides new insights into the mechanism of topoisomerase action and a platform for structure-based drug design of a new class of antibacterial agents against a clinically proven, but conformationally flexible, enzyme class.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bax, Benjamin D -- Chan, Pan F -- Eggleston, Drake S -- Fosberry, Andrew -- Gentry, Daniel R -- Gorrec, Fabrice -- Giordano, Ilaria -- Hann, Michael M -- Hennessy, Alan -- Hibbs, Martin -- Huang, Jianzhong -- Jones, Emma -- Jones, Jo -- Brown, Kristin Koretke -- Lewis, Ceri J -- May, Earl W -- Saunders, Martin R -- Singh, Onkar -- Spitzfaden, Claus E -- Shen, Carol -- Shillings, Anthony -- Theobald, Andrew J -- Wohlkonig, Alexandre -- Pearson, Neil D -- Gwynn, Michael N -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Aug 19;466(7309):935-40. doi: 10.1038/nature09197. Epub 2010 Aug 4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Discovery Research, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK. benjamin.d.bax@gsk.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20686482" target="_blank"〉PubMed〈/a〉
    Keywords: Anti-Bacterial Agents/*chemistry/metabolism/*pharmacology ; Apoenzymes/chemistry/metabolism ; Arginine/metabolism ; Aspartic Acid/metabolism ; Binding Sites ; Catalytic Domain ; Ciprofloxacin/chemistry/metabolism ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; DNA Cleavage ; DNA Gyrase/*chemistry/metabolism ; DNA, Superhelical/chemistry/metabolism ; Drug Design ; Drug Resistance ; Escherichia coli/enzymology ; Manganese/metabolism ; Models, Molecular ; Protein Conformation ; Quinolines/*chemistry/metabolism/*pharmacology ; Quinolones/chemistry/metabolism ; Staphylococcus aureus/*enzymology ; Structure-Activity Relationship ; *Topoisomerase II Inhibitors
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  • 97
    Publication Date: 2010-09-09
    Description: B-RAF is the most frequently mutated protein kinase in human cancers. The finding that oncogenic mutations in BRAF are common in melanoma, followed by the demonstration that these tumours are dependent on the RAF/MEK/ERK pathway, offered hope that inhibition of B-RAF kinase activity could benefit melanoma patients. Herein, we describe the structure-guided discovery of PLX4032 (RG7204), a potent inhibitor of oncogenic B-RAF kinase activity. Preclinical experiments demonstrated that PLX4032 selectively blocked the RAF/MEK/ERK pathway in BRAF mutant cells and caused regression of BRAF mutant xenografts. Toxicology studies confirmed a wide safety margin consistent with the high degree of selectivity, enabling Phase 1 clinical trials using a crystalline formulation of PLX4032 (ref. 5). In a subset of melanoma patients, pathway inhibition was monitored in paired biopsy specimens collected before treatment initiation and following two weeks of treatment. This analysis revealed substantial inhibition of ERK phosphorylation, yet clinical evaluation did not show tumour regressions. At higher drug exposures afforded by a new amorphous drug formulation, greater than 80% inhibition of ERK phosphorylation in the tumours of patients correlated with clinical response. Indeed, the Phase 1 clinical data revealed a remarkably high 81% response rate in metastatic melanoma patients treated at an oral dose of 960 mg twice daily. These data demonstrate that BRAF-mutant melanomas are highly dependent on B-RAF kinase activity.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948082/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948082/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bollag, Gideon -- Hirth, Peter -- Tsai, James -- Zhang, Jiazhong -- Ibrahim, Prabha N -- Cho, Hanna -- Spevak, Wayne -- Zhang, Chao -- Zhang, Ying -- Habets, Gaston -- Burton, Elizabeth A -- Wong, Bernice -- Tsang, Garson -- West, Brian L -- Powell, Ben -- Shellooe, Rafe -- Marimuthu, Adhirai -- Nguyen, Hoa -- Zhang, Kam Y J -- Artis, Dean R -- Schlessinger, Joseph -- Su, Fei -- Higgins, Brian -- Iyer, Raman -- D'Andrea, Kurt -- Koehler, Astrid -- Stumm, Michael -- Lin, Paul S -- Lee, Richard J -- Grippo, Joseph -- Puzanov, Igor -- Kim, Kevin B -- Ribas, Antoni -- McArthur, Grant A -- Sosman, Jeffrey A -- Chapman, Paul B -- Flaherty, Keith T -- Xu, Xiaowei -- Nathanson, Katherine L -- Nolop, Keith -- K24 CA097588/CA/NCI NIH HHS/ -- P50 CA093372/CA/NCI NIH HHS/ -- P50 CA093372-01/CA/NCI NIH HHS/ -- R01 CA118871/CA/NCI NIH HHS/ -- R01 CA118871-01A1/CA/NCI NIH HHS/ -- England -- Nature. 2010 Sep 30;467(7315):596-9. doi: 10.1038/nature09454.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Plexxikon Inc., 91 Bolivar Drive, Berkeley, California 94710, USA. gbollag@plexxikon.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20823850" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Animals ; Dogs ; Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors/metabolism ; Humans ; Indoles/administration & dosage/adverse effects/chemistry/*therapeutic use ; MAP Kinase Signaling System/drug effects ; Macaca fascicularis ; Melanoma/*drug therapy/*enzymology/genetics/pathology ; Models, Molecular ; Mutant Proteins/antagonists & inhibitors/chemistry/genetics/metabolism ; Mutation/*genetics ; Neoplasm Metastasis ; Phosphorylation/drug effects ; Positron-Emission Tomography ; Proto-Oncogene Proteins B-raf/*antagonists & ; inhibitors/chemistry/genetics/metabolism ; Rats ; Substrate Specificity ; Sulfonamides/administration & dosage/adverse effects/chemistry/*therapeutic use ; Xenograft Model Antitumor Assays
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  • 98
    Publication Date: 2010-07-24
    Description: Obesity induced in mice by high-fat feeding activates the protein kinase Cdk5 (cyclin-dependent kinase 5) in adipose tissues. This results in phosphorylation of the nuclear receptor PPARgamma (peroxisome proliferator-activated receptor gamma), a dominant regulator of adipogenesis and fat cell gene expression, at serine 273. This modification of PPARgamma does not alter its adipogenic capacity, but leads to dysregulation of a large number of genes whose expression is altered in obesity, including a reduction in the expression of the insulin-sensitizing adipokine, adiponectin. The phosphorylation of PPARgamma by Cdk5 is blocked by anti-diabetic PPARgamma ligands, such as rosiglitazone and MRL24. This inhibition works both in vivo and in vitro, and is completely independent of classical receptor transcriptional agonism. Similarly, inhibition of PPARgamma phosphorylation in obese patients by rosiglitazone is very tightly associated with the anti-diabetic effects of this drug. All these findings strongly suggest that Cdk5-mediated phosphorylation of PPARgamma may be involved in the pathogenesis of insulin-resistance, and present an opportunity for development of an improved generation of anti-diabetic drugs through PPARgamma.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2987584/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2987584/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Choi, Jang Hyun -- Banks, Alexander S -- Estall, Jennifer L -- Kajimura, Shingo -- Bostrom, Pontus -- Laznik, Dina -- Ruas, Jorge L -- Chalmers, Michael J -- Kamenecka, Theodore M -- Bluher, Matthias -- Griffin, Patrick R -- Spiegelman, Bruce M -- DK087853/DK/NIDDK NIH HHS/ -- DK31405/DK/NIDDK NIH HHS/ -- K99 DK087853/DK/NIDDK NIH HHS/ -- R01 GM084041/GM/NIGMS NIH HHS/ -- R01 GM084041-03/GM/NIGMS NIH HHS/ -- R01-GM084041/GM/NIGMS NIH HHS/ -- R37 DK031405/DK/NIDDK NIH HHS/ -- R37 DK031405-30/DK/NIDDK NIH HHS/ -- S10 RR027270/RR/NCRR NIH HHS/ -- U54 MH084512/MH/NIMH NIH HHS/ -- U54 MH084512-020010/MH/NIMH NIH HHS/ -- U54-MH084512/MH/NIMH NIH HHS/ -- Intramural NIH HHS/ -- England -- Nature. 2010 Jul 22;466(7305):451-6. doi: 10.1038/nature09291.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cancer Biology and Division of Metabolism and Chronic Disease, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20651683" target="_blank"〉PubMed〈/a〉
    Keywords: Adipose Tissue/drug effects/metabolism/physiopathology ; Amino Acid Sequence ; Animals ; Cell Line ; Cyclin-Dependent Kinase 5/*antagonists & inhibitors/genetics/metabolism ; Diabetes Mellitus, Experimental/complications/*drug therapy/metabolism ; Dietary Fats/pharmacology ; Humans ; Insulin/metabolism ; Ligands ; Mice ; Models, Molecular ; Obesity/chemically induced/complications/*metabolism/physiopathology ; PPAR gamma/agonists/*metabolism ; Phosphorylation/drug effects ; Phosphoserine/metabolism ; Protein Conformation ; Thiazolidinediones/*pharmacology/therapeutic use
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  • 99
    Publication Date: 2010-01-26
    Description: Epigenetic reprogramming including demethylation of DNA occurs in mammalian primordial germ cells (PGCs) and in early embryos, and is important for the erasure of imprints and epimutations, and the return to pluripotency. The extent of this reprogramming and its molecular mechanisms are poorly understood. We previously showed that the cytidine deaminases AID and APOBEC1 can deaminate 5-methylcytosine in vitro and in Escherichia coli, and in the mouse are expressed in tissues in which demethylation occurs. Here we profiled DNA methylation throughout the genome by unbiased bisulphite next generation sequencing in wild-type and AID-deficient mouse PGCs at embryonic day (E)13.5. Wild-type PGCs revealed marked genome-wide erasure of methylation to a level below that of methylation deficient (Np95(-/-), also called Uhrf1(-/-)) embryonic stem cells, with female PGCs being less methylated than male ones. By contrast, AID-deficient PGCs were up to three times more methylated than wild-type ones; this substantial difference occurred throughout the genome, with introns, intergenic regions and transposons being relatively more methylated than exons. Relative hypermethylation in AID-deficient PGCs was confirmed by analysis of individual loci in the genome. Our results reveal that erasure of DNA methylation in the germ line is a global process, hence limiting the potential for transgenerational epigenetic inheritance. AID deficiency interferes with genome-wide erasure of DNA methylation patterns, indicating that AID has a critical function in epigenetic reprogramming and potentially in restricting the inheritance of epimutations in mammals.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965733/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965733/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Popp, Christian -- Dean, Wendy -- Feng, Suhua -- Cokus, Shawn J -- Andrews, Simon -- Pellegrini, Matteo -- Jacobsen, Steven E -- Reik, Wolf -- G0700098/Medical Research Council/United Kingdom -- R37 GM060398/GM/NIGMS NIH HHS/ -- R37 GM060398-11/GM/NIGMS NIH HHS/ -- Biotechnology and Biological Sciences Research Council/United Kingdom -- Howard Hughes Medical Institute/ -- Medical Research Council/United Kingdom -- England -- Nature. 2010 Feb 25;463(7284):1101-5. doi: 10.1038/nature08829.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20098412" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cytidine Deaminase/*deficiency/genetics/*metabolism ; *DNA Methylation ; DNA Transposable Elements/genetics ; Embryo, Mammalian/cytology/embryology/metabolism ; Epigenesis, Genetic/genetics ; Exons/genetics ; Female ; *Genome/genetics ; Germ Cells/enzymology/*metabolism ; Introns/genetics ; Male ; Mice ; Mice, Inbred C57BL ; Nuclear Proteins/deficiency/genetics ; Octamer Transcription Factor-3/genetics
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  • 100
    Publication Date: 2010-05-28
    Description: MicroRNAs (miRNAs) mediate post-transcriptional gene regulation through association with Argonaute proteins (AGOs). Crystal structures of archaeal and bacterial homologues of AGOs have shown that the MID (middle) domain mediates the interaction with the phosphorylated 5' end of the miRNA guide strand and this interaction is thought to be independent of the identity of the 5' nucleotide in these systems. However, analysis of the known sequences of eukaryotic miRNAs and co-immunoprecipitation experiments indicate that there is a clear bias for U or A at the 5' position. Here we report the crystal structure of a MID domain from a eukaryotic AGO protein, human AGO2. The structure, in complex with nucleoside monophosphates (AMP, CMP, GMP, and UMP) mimicking the 5' end of miRNAs, shows that there are specific contacts made between the base of UMP or AMP and a rigid loop in the MID domain. Notably, the structure of the loop discriminates against CMP and GMP and dissociation constants calculated from NMR titration experiments confirm these results, showing that AMP (0.26 mM) and UMP (0.12 mM) bind with up to 30-fold higher affinity than either CMP (3.6 mM) or GMP (3.3 mM). This study provides structural evidence for nucleotide-specific interactions in the MID domain of eukaryotic AGO proteins and explains the observed preference for U or A at the 5' end of miRNAs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Frank, Filipp -- Sonenberg, Nahum -- Nagar, Bhushan -- MOP-82929/Canadian Institutes of Health Research/Canada -- England -- Nature. 2010 Jun 10;465(7299):818-22. doi: 10.1038/nature09039. Epub 2010 May 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, McGill University, Montreal, Quebec H3G 0B1, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20505670" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Monophosphate/metabolism ; Argonaute Proteins ; Base Sequence ; Crystallography, X-Ray ; Cytidine Monophosphate/metabolism ; Eukaryotic Initiation Factor-2/*chemistry/*metabolism ; Guanosine Monophosphate/metabolism ; Humans ; Kinetics ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Protein Structure, Tertiary ; RNA, Guide/chemistry/*genetics/*metabolism ; Structure-Activity Relationship ; Substrate Specificity ; Thermodynamics ; Uridine Monophosphate/metabolism
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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