gamma-H2AX dephosphorylation by protein phosphatase 2A facilitates DNA double-strand break repair.
Phosphorylated histone H2AX (gamma-H2AX) forms foci over large chromatin domains surrounding double-stranded DNA breaks (DSB). These foci recruit DSB repair proteins and dissolve during or after repair is completed. How gamma-H2AX is removed from chromatin remains unknown. Here, we show that protein phosphatase 2A (PP2A) is involved in removing gamma-H2AX foci. The PP2A catalytic subunit [PP2A(C)] and gamma-H2AX coimmunoprecipitate and colocalize in DNA damage foci and PP2A dephosphorylates gamma-H2AX in vitro. The recruitment of PP2A(C) to DNA damage foci is H2AX dependent. When PP2A(C) is inhibited or silenced by RNA interference, gamma-H2AX foci persist, DNA repair is inefficient, and cells are hypersensitive to DNA damage. The effect of PP2A on gamma-H2AX levels is independent of ATM, ATR, or DNA-PK activity.
Chowdhury
Dipanjan
D
CBR Institute for Biomedical Research and The Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Keogh
Michael-Christopher
MC
Ishii
Haruhiko
H
Peterson
Craig L
CL
Buratowski
Stephen
S
Lieberman
Judy
J
D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005347:Fibroblasts; D006367:HeLa Cells; D006657:Histones / Q000172:deficiency / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D025521:Tumor Suppressor Proteins; C475961:gamma-H2AX protein, mouse; C576897:Atr protein, mouse; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2