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  • Protein Structure, Tertiary  (4)
  • Nature Publishing Group (NPG)  (4)
  • 1
    Publication Date: 2009-05-29
    Description: The AMP-activated protein kinase (AMPK) is characterized by its ability to bind to AMP, which enables it to adjust enzymatic activity by sensing the cellular energy status and maintain the balance between ATP production and consumption in eukaryotic cells. It also has important roles in the regulation of cell growth and proliferation, and in the establishment and maintenance of cell polarity. These important functions have rendered AMPK an important drug target for obesity, type 2 diabetes and cancer treatments. However, the regulatory mechanism of AMPK activity by AMP binding remains unsolved. Here we report the crystal structures of an unphosphorylated fragment of the AMPK alpha-subunit (KD-AID) from Schizosaccharomyces pombe that contains both the catalytic kinase domain and an autoinhibitory domain (AID), and of a phosphorylated kinase domain from Saccharomyces cerevisiae (Snf1-pKD). The AID binds, from the 'backside', to the hinge region of its kinase domain, forming contacts with both amino-terminal and carboxy-terminal lobes. Structural analyses indicate that AID binding might constrain the mobility of helix alphaC, hence resulting in an autoinhibited KD-AID with much lower kinase activity than that of the kinase domain alone. AMP activates AMPK both allosterically and by inhibiting dephosphorylation. Further in vitro kinetic studies demonstrate that disruption of the KD-AID interface reverses the autoinhibition and these AMPK heterotrimeric mutants no longer respond to the change in AMP concentration. The structural and biochemical data have shown the primary mechanism of AMPK autoinhibition and suggest a conformational switch model for AMPK activation by AMP.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Lei -- Jiao, Zhi-Hao -- Zheng, Li-Sha -- Zhang, Yuan-Yuan -- Xie, Shu-Tao -- Wang, Zhi-Xin -- Wu, Jia-Wei -- England -- Nature. 2009 Jun 25;459(7250):1146-9. doi: 10.1038/nature08075. Epub 2009 May 27.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MOE Key Laboratory of Bioinformatics, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19474788" target="_blank"〉PubMed〈/a〉
    Keywords: AMP-Activated Protein Kinases/*chemistry/*metabolism ; Adenosine Monophosphate/metabolism ; Amino Acid Sequence ; Animals ; *Models, Molecular ; Molecular Sequence Data ; Mutation ; Phosphorylation ; Protein Structure, Tertiary ; Rats ; Saccharomyces cerevisiae/*enzymology ; Schizosaccharomyces/*enzymology ; Sequence Alignment
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2015-07-30
    Description: DNA replication in eukaryotes is strictly regulated by several mechanisms. A central step in this replication is the assembly of the heterohexameric minichromosome maintenance (MCM2-7) helicase complex at replication origins during G1 phase as an inactive double hexamer. Here, using cryo-electron microscopy, we report a near-atomic structure of the MCM2-7 double hexamer purified from yeast G1 chromatin. Our structure shows that two single hexamers, arranged in a tilted and twisted fashion through interdigitated amino-terminal domain interactions, form a kinked central channel. Four constricted rings consisting of conserved interior beta-hairpins from the two single hexamers create a narrow passageway that tightly fits duplex DNA. This narrow passageway, reinforced by the offset of the two single hexamers at the double hexamer interface, is flanked by two pairs of gate-forming subunits, MCM2 and MCM5. These unusual features of the twisted and tilted single hexamers suggest a concerted mechanism for the melting of origin DNA that requires structural deformation of the intervening DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Ningning -- Zhai, Yuanliang -- Zhang, Yixiao -- Li, Wanqiu -- Yang, Maojun -- Lei, Jianlin -- Tye, Bik-Kwoon -- Gao, Ning -- England -- Nature. 2015 Aug 13;524(7564):186-91. doi: 10.1038/nature14685. Epub 2015 Jul 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China. ; 1] Division of Life Science, Hong Kong Universityof Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China [2] Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. ; 1] Division of Life Science, Hong Kong Universityof Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China [2] Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26222030" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Cell Cycle Proteins/chemistry/metabolism/ultrastructure ; Chromatin/chemistry ; Conserved Sequence ; *Cryoelectron Microscopy ; DNA/chemistry/metabolism/ultrastructure ; DNA-Directed DNA Polymerase/chemistry/ultrastructure ; G1 Phase ; Minichromosome Maintenance Proteins/*chemistry/metabolism/*ultrastructure ; Models, Biological ; Models, Molecular ; Multienzyme Complexes/chemistry/ultrastructure ; Nucleic Acid Denaturation ; Protein Binding ; Protein Multimerization ; Protein Structure, Tertiary ; Protein Subunits/*chemistry/metabolism ; Replication Origin ; Saccharomyces cerevisiae/*chemistry/*ultrastructure ; Saccharomyces cerevisiae Proteins/chemistry/metabolism/ultrastructure
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2012-05-12
    Description: R-spondin proteins strongly potentiate Wnt signalling and function as stem-cell growth factors. Despite the biological and therapeutic significance, the molecular mechanism of R-spondin action remains unclear. Here we show that the cell-surface transmembrane E3 ubiquitin ligase zinc and ring finger 3 (ZNRF3) and its homologue ring finger 43 (RNF43) are negative feedback regulators of Wnt signalling. ZNRF3 is associated with the Wnt receptor complex, and inhibits Wnt signalling by promoting the turnover of frizzled and LRP6. Inhibition of ZNRF3 enhances Wnt/beta-catenin signalling and disrupts Wnt/planar cell polarity signalling in vivo. Notably, R-spondin mimics ZNRF3 inhibition by increasing the membrane level of Wnt receptors. Mechanistically, R-spondin interacts with the extracellular domain of ZNRF3 and induces the association between ZNRF3 and LGR4, which results in membrane clearance of ZNRF3. These data suggest that R-spondin enhances Wnt signalling by inhibiting ZNRF3. Our study provides new mechanistic insights into the regulation of Wnt receptor turnover, and reveals ZNRF3 as a tractable target for therapeutic exploration.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hao, Huai-Xiang -- Xie, Yang -- Zhang, Yue -- Charlat, Olga -- Oster, Emma -- Avello, Monika -- Lei, Hong -- Mickanin, Craig -- Liu, Dong -- Ruffner, Heinz -- Mao, Xiaohong -- Ma, Qicheng -- Zamponi, Raffaella -- Bouwmeester, Tewis -- Finan, Peter M -- Kirschner, Marc W -- Porter, Jeffery A -- Serluca, Fabrizio C -- Cong, Feng -- England -- Nature. 2012 Apr 29;485(7397):195-200. doi: 10.1038/nature11019.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22575959" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Polarity/physiology ; Colorectal Neoplasms/genetics ; DNA-Binding Proteins/deficiency/genetics/metabolism ; Feedback, Physiological ; Female ; Frizzled Receptors/metabolism ; HEK293 Cells ; Humans ; Low Density Lipoprotein Receptor-Related Protein-6/metabolism ; Male ; Mice ; Mice, Knockout ; Oncogene Proteins/deficiency/genetics/metabolism ; Protein Stability ; Protein Structure, Tertiary ; Receptors, G-Protein-Coupled/deficiency/genetics/metabolism ; Receptors, Wnt/*metabolism ; Thrombospondins/*metabolism ; Ubiquitin-Protein Ligases/chemistry/*deficiency/genetics/*metabolism ; Ubiquitination ; Wnt Signaling Pathway ; Xenopus ; Zebrafish ; beta Catenin/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2016-02-24
    Description: All Gram-negative bacteria, mitochondria and chloroplasts have outer membrane proteins (OMPs) that perform many fundamental biological processes. The OMPs in Gram-negative bacteria are inserted and folded into the outer membrane by the beta-barrel assembly machinery (BAM). The mechanism involved is poorly understood, owing to the absence of a structure of the entire BAM complex. Here we report two crystal structures of the Escherichia coli BAM complex in two distinct states: an inward-open state and a lateral-open state. Our structures reveal that the five polypeptide transport-associated domains of BamA form a ring architecture with four associated lipoproteins, BamB-BamE, in the periplasm. Our structural, functional studies and molecular dynamics simulations indicate that these subunits rotate with respect to the integral membrane beta-barrel of BamA to induce movement of the beta-strands of the barrel and promote insertion of the nascent OMP.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gu, Yinghong -- Li, Huanyu -- Dong, Haohao -- Zeng, Yi -- Zhang, Zhengyu -- Paterson, Neil G -- Stansfeld, Phillip J -- Wang, Zhongshan -- Zhang, Yizheng -- Wang, Wenjian -- Dong, Changjiang -- G1100110/1/Medical Research Council/United Kingdom -- WT106121MA/Wellcome Trust/United Kingdom -- England -- Nature. 2016 Mar 3;531(7592):64-9. doi: 10.1038/nature17199. Epub 2016 Feb 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK. ; Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK. ; Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. ; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou 221004, China. ; Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, College of Life Sciences, Sichuan University, Chengdu 610064, China. ; Laboratory of Department of Surgery, the First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, Guangdong 510080, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26901871" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Outer Membrane Proteins/*chemistry/*metabolism ; Crystallography, X-Ray ; Escherichia coli/*chemistry ; Escherichia coli Proteins/*chemistry/*metabolism ; Lipoproteins/chemistry/metabolism ; Models, Molecular ; Molecular Dynamics Simulation ; Movement ; Multiprotein Complexes/*chemistry/*metabolism ; Periplasm/metabolism ; Protein Binding ; Protein Structure, Tertiary ; Protein Subunits/chemistry/metabolism ; Rotation
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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