Optimal function of the DNA repair enzyme TDP1 requires its phosphorylation by ATM and/or DNA-PK.
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.
Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA.
Benu Brata
BB
Das
Smitha
S
Antony
Shalu
S
Gupta
Thomas S
TS
Dexheimer
Christophe E
CE
Redon
Susan
S
Garfield
Yosef
Y
Shiloh
Yves
Y
Pommier
D001260:Ataxia Telangiectasia / Q000201:enzymology / Q000235:genetics; D064007:Ataxia Telangiectasia Mutated Proteins; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D002470:Cell Survival / Q000235:genetics; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics; D051747:DNA-Activated Protein Kinase / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006801:Humans; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation / Q000235:genetics; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D012694:Serine / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D000076105:X-ray Repair Cross Complementing Protein 1
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D012694:Serine; D002334:Carnitine O-Palmitoyltransferase; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D010727:Phosphoric Diester Hydrolases; C498508:TDP1 protein, human