Abstract
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.
Publication types
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Research Support, N.I.H., Intramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Ataxia Telangiectasia / enzymology
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Ataxia Telangiectasia / genetics
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Ataxia Telangiectasia Mutated Proteins
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Carnitine O-Palmitoyltransferase / genetics
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Cell Cycle Proteins / chemistry*
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Cell Cycle Proteins / metabolism
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Cell Cycle Proteins / physiology
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Cell Survival / genetics
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DNA Breaks, Double-Stranded
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DNA Repair* / genetics
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DNA-Activated Protein Kinase / chemistry*
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DNA-Activated Protein Kinase / metabolism
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DNA-Activated Protein Kinase / physiology
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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DNA-Binding Proteins / physiology
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Humans
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Phosphoric Diester Hydrolases / chemistry
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Phosphoric Diester Hydrolases / metabolism*
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Phosphoric Diester Hydrolases / physiology
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Phosphorylation / genetics
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Protein Processing, Post-Translational
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Protein Serine-Threonine Kinases / chemistry*
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Protein Serine-Threonine Kinases / metabolism
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Protein Serine-Threonine Kinases / physiology
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Serine / metabolism
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Tumor Suppressor Proteins / chemistry*
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Tumor Suppressor Proteins / metabolism
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Tumor Suppressor Proteins / physiology
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X-ray Repair Cross Complementing Protein 1
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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Tumor Suppressor Proteins
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X-ray Repair Cross Complementing Protein 1
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XRCC1 protein, human
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Serine
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Carnitine O-Palmitoyltransferase
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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DNA-Activated Protein Kinase
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Protein Serine-Threonine Kinases
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Phosphoric Diester Hydrolases
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TDP1 protein, human