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  • The EMBO Journal advance online publication 22 October 2009; doi:10.1038/emboj.2009.302

Optimal function of the DNA repair enzyme TDP1 requires its phosphorylation by ATM and/or DNA-PK

Benu Brata Das1, Smitha Antony1, Shalu Gupta1, Thomas S Dexheimer1, Christophe E Redon1, Susan Garfield2, Yosef Shiloh3 and Yves Pommier1

  1. Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
  2. Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
  3. The David and Inez Meyers Laboratory for Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel

Correspondence to:

Yves Pommier, Laboratory of Molecular Pharmacology, Division of Basic Sciences, National Institutes of Health, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, Bethesda, MD 20892-4255, USA. Tel.: +1 301 496 5944; Fax: +1 301 402 0752; E-mail: pommier@nih.gov

Received 12 May 2009; Accepted 10 September 2009

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 (gammaH2AX). 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.

  • Keywords:

    • camptothecin,
    • DNA repair,
    • gammaH2AX,
    • Topoisomerase 1,
    • XRCC1