title: The SNF2 family ATPase LSH promotes phosphorylation of H2AX and efficient repair of DNA double-strand breaks in mammalian cells.
abstract: LSH, a protein related to the SNF2 family of chromatin-remodelling ATPases, is essential for the correct establishment of DNA methylation levels and patterns in plants and mammalian cells. However, some of the phenotypes resulting from LSH deficiency cannot be explained easily by defects in DNA methylation. Here we show that LSH-deficient mouse and human fibroblasts show reduced viability after exposure to ionizing radiation and repair DNA double-strand breaks less efficiently than wild-type cells. A more detailed characterisation of this phenotype revealed that, in the absence of LSH, the histone variant H2AX is not efficiently phosphorylated in response to DNA damage. This results in impaired recruitment of MDC1 and 53BP1 proteins to DNA double-strand breaks and compromises phosphorylation of checkpoint kinase CHK2. Furthermore, we demonstrate that the ability of LSH to hydrolyse ATP is necessary for efficient phosphorylation of H2AX at DNA double-strand breaks and successful repair of DNA damage. Taken together, our data reveal a previously unsuspected role of LSH ATPase in the maintenance of genome stability in mammalian somatic cells, which is independent of its function in de novo DNA methylation during development.
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Mayfield Road, Edinburgh EH9 3JR,  UK.
authors.forename: Joe
authors.initials: J
authors.lastname: Burrage
authors.forename: Ausma
authors.initials: A
authors.lastname: Termanis
authors.forename: Andreas
authors.initials: A
authors.lastname: Geissner
authors.forename: Kevin
authors.initials: K
authors.lastname: Myant
authors.forename: Katrina
authors.initials: K
authors.lastname: Gordon
authors.forename: Irina
authors.initials: I
authors.lastname: Stancheva
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D018797:Cell Cycle Proteins; D064447:Checkpoint Kinase 2; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004265:DNA Helicases / Q000172:deficiency / Q000378:metabolism*; D019175:DNA Methylation / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D004789:Enzyme Activation / Q000528:radiation effects; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D006657:Histones / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007700:Kinetics; D008322:Mammals / Q000378:metabolism; D051379:Mice; D050505:Mutant Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011839:Radiation, Ionizing; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000528:radiation effects; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases; D018797:Cell Cycle Proteins; D064447:Checkpoint Kinase 2; D004265:DNA Helicases; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D050505:Mutant Proteins; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C468783:H2AX protein, human; C508937:MDC1 protein, mouse; C578634:CHEK2 protein, human; C578633:Chek2 protein, mouse; C499333:SNF2 protein, S cerevisiae; C412063:HELLS protein, human; C491758:lymphoid specific helicase, mouse; C475961:gamma-H2AX protein, mouse