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  • 1
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    Structural insight into substrate preference for TET-mediated oxidation (2015)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2015-11-03
    Description: DNA methylation is an important epigenetic modification. Ten-eleven translocation (TET) proteins are involved in DNA demethylation through iteratively oxidizing 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Here we show that human TET1 and TET2 are more active on 5mC-DNA than 5hmC/5fC-DNA substrates. We determine the crystal structures of TET2-5hmC-DNA and TET2-5fC-DNA complexes at 1.80 A and 1.97 A resolution, respectively. The cytosine portion of 5hmC/5fC is specifically recognized by TET2 in a manner similar to that of 5mC in the TET2-5mC-DNA structure, and the pyrimidine base of 5mC/5hmC/5fC adopts an almost identical conformation within the catalytic cavity. However, the hydroxyl group of 5hmC and carbonyl group of 5fC face towards the opposite direction because the hydroxymethyl group of 5hmC and formyl group of 5fC adopt restrained conformations through forming hydrogen bonds with the 1-carboxylate of NOG and N4 exocyclic nitrogen of cytosine, respectively. Biochemical analyses indicate that the substrate preference of TET2 results from the different efficiencies of hydrogen abstraction in TET2-mediated oxidation. The restrained conformation of 5hmC and 5fC within the catalytic cavity may prevent their abstractable hydrogen(s) adopting a favourable orientation for hydrogen abstraction and thus result in low catalytic efficiency. Our studies demonstrate that the substrate preference of TET2 results from the intrinsic value of its substrates at their 5mC derivative groups and suggest that 5hmC is relatively stable and less prone to further oxidation by TET proteins. Therefore, TET proteins are evolutionarily tuned to be less reactive towards 5hmC and facilitate the generation of 5hmC as a potentially stable mark for regulatory functions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hu, Lulu -- Lu, Junyan -- Cheng, Jingdong -- Rao, Qinhui -- Li, Ze -- Hou, Haifeng -- Lou, Zhiyong -- Zhang, Lei -- Li, Wei -- Gong, Wei -- Liu, Mengjie -- Sun, Chang -- Yin, Xiaotong -- Li, Jie -- Tan, Xiangshi -- Wang, Pengcheng -- Wang, Yinsheng -- Fang, Dong -- Cui, Qiang -- Yang, Pengyuan -- He, Chuan -- Jiang, Hualiang -- Luo, Cheng -- Xu, Yanhui -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Nov 5;527(7576):118-22. doi: 10.1038/nature15713. Epub 2015 Oct 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China. ; Key Laboratory of Molecular Medicine, Ministry of Education, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China. ; State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200433, China. ; Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China. ; Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. ; Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China. ; MOE Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing 100084, China. ; Department of Chemistry, University of California-Riverside, Riverside, California 92521-0403, USA. ; Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA. ; Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA. ; Howard Hughes Medical Institute, 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/26524525" target="_blank"〉PubMed〈/a〉
    Keywords: 5-Methylcytosine/metabolism ; Biocatalysis ; Catalytic Domain ; Crystallography, X-Ray ; Cytosine/analogs & derivatives/metabolism ; DNA/*chemistry/*metabolism ; DNA Methylation ; DNA-Binding Proteins/*chemistry/*metabolism ; Humans ; Hydrogen Bonding ; Models, Molecular ; Oxidation-Reduction ; Protein Binding ; Proto-Oncogene Proteins/*chemistry/*metabolism ; Substrate Specificity
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 2
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    Signalling thresholds and negative B-cell selection in acute lymphoblastic leukaemia (2015)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2015-03-25
    Description: B cells are selected for an intermediate level of B-cell antigen receptor (BCR) signalling strength: attenuation below minimum (for example, non-functional BCR) or hyperactivation above maximum (for example, self-reactive BCR) thresholds of signalling strength causes negative selection. In approximately 25% of cases, acute lymphoblastic leukaemia (ALL) cells carry the oncogenic BCR-ABL1 tyrosine kinase (Philadelphia chromosome positive), which mimics constitutively active pre-BCR signalling. Current therapeutic approaches are largely focused on the development of more potent tyrosine kinase inhibitors to suppress oncogenic signalling below a minimum threshold for survival. We tested the hypothesis that targeted hyperactivation--above a maximum threshold--will engage a deletional checkpoint for removal of self-reactive B cells and selectively kill ALL cells. Here we find, by testing various components of proximal pre-BCR signalling in mouse BCR-ABL1 cells, that an incremental increase of Syk tyrosine kinase activity was required and sufficient to induce cell death. Hyperactive Syk was functionally equivalent to acute activation of a self-reactive BCR on ALL cells. Despite oncogenic transformation, this basic mechanism of negative selection was still functional in ALL cells. Unlike normal pre-B cells, patient-derived ALL cells express the inhibitory receptors PECAM1, CD300A and LAIR1 at high levels. Genetic studies revealed that Pecam1, Cd300a and Lair1 are critical to calibrate oncogenic signalling strength through recruitment of the inhibitory phosphatases Ptpn6 (ref. 7) and Inpp5d (ref. 8). Using a novel small-molecule inhibitor of INPP5D (also known as SHIP1), we demonstrated that pharmacological hyperactivation of SYK and engagement of negative B-cell selection represents a promising new strategy to overcome drug resistance in human ALL.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441554/" 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/PMC4441554/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Zhengshan -- Shojaee, Seyedmehdi -- Buchner, Maike -- Geng, Huimin -- Lee, Jae Woong -- Klemm, Lars -- Titz, Bjorn -- Graeber, Thomas G -- Park, Eugene -- Tan, Ying Xim -- Satterthwaite, Anne -- Paietta, Elisabeth -- Hunger, Stephen P -- Willman, Cheryl L -- Melnick, Ari -- Loh, Mignon L -- Jung, Jae U -- Coligan, John E -- Bolland, Silvia -- Mak, Tak W -- Limnander, Andre -- Jumaa, Hassan -- Reth, Michael -- Weiss, Arthur -- Lowell, Clifford A -- Muschen, Markus -- 101880/Wellcome Trust/United Kingdom -- CA180794/CA/NCI NIH HHS/ -- CA180820/CA/NCI NIH HHS/ -- R01 AI068150/AI/NIAID NIH HHS/ -- R01 AI113272/AI/NIAID NIH HHS/ -- R01 CA137060/CA/NCI NIH HHS/ -- R01 CA139032/CA/NCI NIH HHS/ -- R01 CA157644/CA/NCI NIH HHS/ -- R01 CA169458/CA/NCI NIH HHS/ -- R01 CA172558/CA/NCI NIH HHS/ -- R01CA137060/CA/NCI NIH HHS/ -- R01CA139032/CA/NCI NIH HHS/ -- R01CA157644/CA/NCI NIH HHS/ -- R01CA169458/CA/NCI NIH HHS/ -- R01CA172558/CA/NCI NIH HHS/ -- U01 CA157937/CA/NCI NIH HHS/ -- U10 CA180794/CA/NCI NIH HHS/ -- U10 CA180820/CA/NCI NIH HHS/ -- U10 CA180827/CA/NCI NIH HHS/ -- U10 CA180886/CA/NCI NIH HHS/ -- U24 CA114737/CA/NCI NIH HHS/ -- U24 CA196172/CA/NCI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 May 21;521(7552):357-61. doi: 10.1038/nature14231. Epub 2015 Mar 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA. ; Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095, USA. ; Rosalind Russell-Ephraim P. Engleman Medical Research Center for Arthritis, Division of Rheumatology, Department of Medicine, Howard Hughes Medical Institute, University of California, San Francisco, California 94143, USA. ; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA. ; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10466, USA. ; Division of Pediatric Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Philadelphia 19104, USA. ; University of New Mexico Cancer Center, Albuquerque, New Mexico 87102, USA. ; Departments of Medicine and Pharmacology, Weill Cornell Medical College, New York, New York 10065, USA. ; Pediatric Hematology-Oncology, University of California, San Francisco, California 94143, USA. ; Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA. ; Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA. ; Autoimmunity and Functional Genomics Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA. ; The Campbell Family Institute for Breast Cancer Research, University Health Network, 620 University Avenue, Toronto, Ontario M5G 2M9, Canada. ; Department of Anatomy, University of California, San Francisco, California 94143, USA. ; Institute of Immunology, University Clinics Ulm, 89081 Ulm, Germany. ; BIOSS Centre for Biological Signalling Studies and Faculty of Biology, Albert-Ludwigs-Universitat Freiburg, and MPI of Immunbiologie and Epigenetics, 79104 Freiburg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25799995" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs/genetics ; Animals ; Antigens, CD/metabolism ; Antigens, CD31/metabolism ; B-Lymphocytes/drug effects/*metabolism/*pathology ; Cell Death/drug effects ; Cell Line, Tumor ; Cell Transformation, Neoplastic ; Disease Models, Animal ; Drug Resistance, Neoplasm/drug effects ; Enzyme Activation/drug effects ; Female ; Fusion Proteins, bcr-abl/genetics ; Gene Deletion ; Humans ; Intracellular Signaling Peptides and Proteins/agonists/metabolism ; Mice ; Mice, Inbred NOD ; Mice, SCID ; Phosphoric Monoester Hydrolases/antagonists & inhibitors/metabolism ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug ; therapy/genetics/*metabolism/*pathology ; Precursor Cells, B-Lymphoid/drug effects/metabolism/pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6/deficiency/genetics/metabolism ; Protein-Tyrosine Kinases/metabolism ; Receptors, Antigen, B-Cell/deficiency/genetics/metabolism ; Receptors, Immunologic/genetics/metabolism ; *Signal Transduction/drug effects ; Tyrosine/metabolism ; Xenograft Model Antitumor Assays
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
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