A PP4-Phosphatase Complex Dephosphorylates γ-H2AX Generated during DNA Replication

Dipanjan Chowdhury, Xingzhi Xu, Xueyan Zhong, Fariyal Ahmed, Jianing Zhong, Ji Liao, Derek M Dykxhoorn, David M. Weinstock, Gerd P. Pfeifer, Judy Lieberman

Research output: Contribution to journalArticle

160 Citations (Scopus)

Abstract

The histone H2A variant H2AX is rapidly phosphorylated in response to DNA double-stranded breaks to produce γ-H2AX. γ-H2AX stabilizes cell-cycle checkpoint proteins and DNA repair factors at the break site. We previously found that the protein phosphatase PP2A is required to resolve γ-H2AX foci and complete DNA repair after exogenous DNA damage. Here we describe a three-protein PP4 phosphatase complex in mammalian cells, containing PP4C, PP4R2, and PP4R3β, that specifically dephosphorylates ATR-mediated γ-H2AX generated during DNA replication. PP4 efficiently dephosphorylates γ-H2AX within mononucleosomes in vitro and does not directly alter ATR or checkpoint kinase activity, suggesting that PP4 acts directly on γ-H2AX in cells. When the PP4 complex is silenced, repair of DNA replication-mediated breaks is inefficient, and cells are hypersensitive to DNA replication inhibitors, but not radiomimetic drugs. Therefore, γ-H2AX elimination at DNA damage foci is required for DNA damage repair, but accomplishing this task involves distinct phosphatases with potentially overlapping roles.

Original languageEnglish
Pages (from-to)33-46
Number of pages14
JournalMolecular Cell
Volume31
Issue number1
DOIs
StatePublished - Jul 11 2008
Externally publishedYes

Fingerprint

DNA Replication
Phosphoric Monoester Hydrolases
DNA Repair
DNA Damage
Phosphoprotein Phosphatases
Cell Cycle Proteins
Double-Stranded DNA Breaks
Cell Cycle Checkpoints
Histones
Phosphotransferases
Pharmaceutical Preparations

Keywords

  • DNA
  • SIGNALING

ASJC Scopus subject areas

  • Molecular Biology

Cite this

Chowdhury, D., Xu, X., Zhong, X., Ahmed, F., Zhong, J., Liao, J., ... Lieberman, J. (2008). A PP4-Phosphatase Complex Dephosphorylates γ-H2AX Generated during DNA Replication. Molecular Cell, 31(1), 33-46. https://doi.org/10.1016/j.molcel.2008.05.016

A PP4-Phosphatase Complex Dephosphorylates γ-H2AX Generated during DNA Replication. / Chowdhury, Dipanjan; Xu, Xingzhi; Zhong, Xueyan; Ahmed, Fariyal; Zhong, Jianing; Liao, Ji; Dykxhoorn, Derek M; Weinstock, David M.; Pfeifer, Gerd P.; Lieberman, Judy.

In: Molecular Cell, Vol. 31, No. 1, 11.07.2008, p. 33-46.

Research output: Contribution to journalArticle

Chowdhury, D, Xu, X, Zhong, X, Ahmed, F, Zhong, J, Liao, J, Dykxhoorn, DM, Weinstock, DM, Pfeifer, GP & Lieberman, J 2008, 'A PP4-Phosphatase Complex Dephosphorylates γ-H2AX Generated during DNA Replication', Molecular Cell, vol. 31, no. 1, pp. 33-46. https://doi.org/10.1016/j.molcel.2008.05.016
Chowdhury, Dipanjan ; Xu, Xingzhi ; Zhong, Xueyan ; Ahmed, Fariyal ; Zhong, Jianing ; Liao, Ji ; Dykxhoorn, Derek M ; Weinstock, David M. ; Pfeifer, Gerd P. ; Lieberman, Judy. / A PP4-Phosphatase Complex Dephosphorylates γ-H2AX Generated during DNA Replication. In: Molecular Cell. 2008 ; Vol. 31, No. 1. pp. 33-46.
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