Ubiquitylation of Ku80 by RNF126 Promotes Completion of Nonhomologous End Joining-Mediated DNA Repair.

Noriko Ishida, Tadashi Nakagawa, Shun-Ichiro Iemura, Akira Yasui, Hiroki Shima, Yasutake Katoh, Yuko Nagasawa, Toru Natsume, Kazuhiko Igarashi, Keiko Nakayama

Molecular and cellular biology 2017 Feb 15

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Repair of damaged DNA is critical for maintenance of genetic information. In eukaryotes, DNA double-strand breaks (DSBs) are recognized by the Ku70-Ku80 heterodimer, which then recruits proteins that mediate repair by nonhomologous end joining (NHEJ). Prolonged retention of Ku70/80 at DSBs prevents completion of repair, however, with ubiquitylation of Ku80 having been implicated in Ku70/80 dissociation from DNA. Here, we identify RNF126 as a ubiquitin ligase that is recruited to DSBs and ubiquitylates Ku80, with UBE2D3 serving as an E2 enzyme. Knockdown of RNF126 prevented Ku70/80 dissociation from DSBs and inhibited break repair. Attenuation of Ku80 ubiquitylation by replacement of ubiquitylation site lysines with arginine residues delayed Ku70/80 release from chromatin after DSB induction by genotoxic insults. Together, our data indicate that RNF126 is a novel regulator of NHEJ that promotes completion of DNA repair by ubiquitylating Ku80 and releasing Ku70/80 from damaged DNA. Copyright © 2017 American Society for Microbiology.

Citation

Noriko Ishida, Tadashi Nakagawa, Shun-Ichiro Iemura, Akira Yasui, Hiroki Shima, Yasutake Katoh, Yuko Nagasawa, Toru Natsume, Kazuhiko Igarashi, Keiko Nakayama. Ubiquitylation of Ku80 by RNF126 Promotes Completion of Nonhomologous End Joining-Mediated DNA Repair. Molecular and cellular biology. 2017 Feb 15;37(4)