title: Wild-type p53-induced phosphatase 1 dephosphorylates histone variant gamma-H2AX and suppresses DNA double strand break repair.
abstract: In response to DNA double strand breaks, the histone variant H2AX at the break site is phosphorylated at serine 139 by DNA damage sensor kinases such as ataxia telangiectasia-mutated, forming gamma-H2AX. This phosphorylation event is critical for sustained recruitment of other proteins to repair the break. After repair, restoration of the cell to a prestress state is associated with gamma-H2AX dephosphorylation and dissolution of gamma-H2AX-associated damage foci. The phosphatases PP2A and PP4 have previously been shown to dephosphorylate gamma-H2AX. Here, we demonstrate that the wild-type p53-induced phosphatase 1 (WIP1) also dephosphorylates gamma-H2AX at serine 139 in vitro and in vivo. Overexpression of WIP1 reduces formation of gamma-H2AX foci in response to ionizing and ultraviolet radiation and blocks recruitment of MDC1 (mediator of DNA damage checkpoint 1) and 53BP1 (p53 binding protein 1) to DNA damage foci. Finally, these inhibitory effects of WIP1 on gamma-H2AX are accompanied by WIP1 suppression of DNA double strand break repair. Thus, WIP1 has a homeostatic role in reversing the effects of ataxia telangiectasia-mutated phosphorylation of H2AX.
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Moon
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Xinna
authors.initials: X
authors.lastname: Zhang
authors.forename: Thuy-Ai
authors.initials: TA
authors.lastname: Nguyen
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Darlington
authors.forename: Alan S
authors.initials: AS
authors.lastname: Waldman
authors.forename: Xiongbin
authors.initials: X
authors.lastname: Lu
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Donehower
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000502:physiology* / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005720:Gamma Rays; D006367:HeLa Cells; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology / Q000528:radiation effects; D000071636:Protein Phosphatase 2C; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D000071857:Tumor Suppressor p53-Binding Protein 1; D014466:Ultraviolet Rays; D014916:Whole-Body Irradiation
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C; D017346:Protein Serine-Threonine Kinases; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D000071857:Tumor Suppressor p53-Binding Protein 1; C468783:H2AX protein, human; C413163:MDC1 protein, human; C508937:MDC1 protein, mouse; C495901:TP53 protein, human; C498301:TP53BP1 protein, human; C498302:Trp53bp1 protein, mouse; C576324:ATM protein, human; C576325:Atm protein, mouse; C000607458:PPM1D protein, human; C000607468:Ppm1d protein, mouse; C475961:gamma-H2AX protein, mouse