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Optimal function of the DNA repair enzyme TDP1 requires its phosphorylation by ATM and/or DNA‐PK
Author(s) -
Das Benu Brata,
Antony Smitha,
Gupta Shalu,
Dexheimer Thomas S,
Redon Christophe E,
Garfield Susan,
Shiloh Yosef,
Pommier Yves
Publication year - 2009
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2009.302
Subject(s) - biology , dna , phosphorylation , dna repair , enzyme , function (biology) , dna damage , biochemistry , genetics , microbiology and biotechnology
Human tyrosyl–DNA phosphodiesterase (TDP1) hydrolyzes the phosphodiester bond at a DNA 3′ end linked to a tyrosyl moiety. This type of linkage is found at stalled topoisomerase I (Top1)–DNA covalent complexes, and TDP1 has been implicated in the repair of such complexes. Here we show that Top1‐associated DNA double‐stranded breaks (DSBs) induce the phosphorylation of TDP1 at S81. This phosphorylation is mediated by the protein kinases: ataxia‐telangiectasia‐mutated (ATM) and DNA‐dependent protein kinase (DNA‐PK). Phosphorylated TDP1 forms nuclear foci that co‐localize with those of phosphorylated histone H2AX (γH2AX). Both Top1‐induced replication‐ and transcription‐mediated DNA damages induce TDP1 phosphorylation. Furthermore, we show that S81 phosphorylation stabilizes TDP1, induces the formation of XRCC1 (X‐ray cross‐complementing group 1)–TDP1 complexes and enhances the mobilization of TDP1 to DNA damage sites. Finally, we provide evidence that TDP1–S81 phosphorylation promotes cell survival and DNA repair in response to CPT‐induced DSBs. Together; our findings provide a new mechanism for TDP1 post‐translational regulation by ATM and DNA‐PK.