Segal-Raz H, Mass G, Baranes-Bachar K, Lerenthal Y, Wang SY, Chung YM, Ziv-Lehrman S, Ström CE, Helleday T, Hu MCT, Chen DJ, Shiloh Y. ATM-mediated phosphorylation of polynucleotide kinase/phosphatase is required for effective DNA double-strand break repair.
EMBO Rep 2011;
12:713-9. [PMID:
21637298 DOI:
10.1038/embor.2011.96]
[Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 04/17/2011] [Accepted: 04/19/2011] [Indexed: 11/09/2022] Open
Abstract
The cellular response to double-strand breaks (DSBs) in DNA is a complex signalling network, mobilized by the nuclear protein kinase ataxia-telangiectasia mutated (ATM), which phosphorylates many factors in the various branches of this network. A main question is how ATM regulates DSB repair. Here, we identify the DNA repair enzyme polynucleotide kinase/phosphatase (PNKP) as an ATM target. PNKP phosphorylates 5'-OH and dephosphorylates 3'-phosphate DNA ends that are formed at DSB termini caused by DNA-damaging agents, thereby regenerating legitimate ends for further processing. We establish that the ATM phosphorylation targets on human PNKP-Ser 114 and Ser 126-are crucial for cellular survival following DSB induction and for effective DSB repair, being essential for damage-induced enhancement of the activity of PNKP and its proper accumulation at the sites of DNA damage. These findings show a direct functional link between ATM and the DSB-repair machinery.
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