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Sci Rep. 2018 Dec 17;8(1):17891. doi: 10.1038/s41598-018-36235-0.

The deubiquitylating enzyme UCHL3 regulates Ku80 retention at sites of DNA damage.

Author information

1
The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, United Kingdom. rnishi@fc.ritsumei.ac.jp.
2
Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan. rnishi@fc.ritsumei.ac.jp.
3
The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, United Kingdom.
4
Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom.
5
Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan.
6
Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, United Kingdom.
7
Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge, CB2 1GA, United Kingdom.

Abstract

Non-homologous end-joining (NHEJ), which can promote genomic instability when dysfunctional, is a major DNA double-strand break (DSB) repair pathway. Although ubiquitylation of the core NHEJ factor, Ku (Ku70-Ku80), which senses broken DNA ends, is important for its removal from sites of damage upon completion of NHEJ, the mechanism regulating Ku ubiquitylation remains elusive. We provide evidence showing that the ubiquitin carboxyl-terminal hydrolase L3 (UCHL3) interacts with and directly deubiquitylates one of the Ku heterodimer subunits, Ku80. Additionally, depleting UCHL3 resulted in reduced Ku80 foci formation, Ku80 binding to chromatin after DSB induction, moderately sensitized cells to ionizing radiation and decreased NHEJ efficiencies. Mechanistically, we show that DNA damage induces UCHL3 phosphorylation, which is dependent on ATM, downstream NHEJ factors and UCHL3 catalytic activity. Furthermore, this phosphorylation destabilizes UCHL3, despite having no effect on its catalytic activity. Collectively, these data suggest that UCHL3 facilitates cellular viability after DSB induction by antagonizing Ku80 ubiquitylation to enhance Ku80 retention at sites of damage.

PMID:
30559450
PMCID:
PMC6297141
DOI:
10.1038/s41598-018-36235-0
[Indexed for MEDLINE]
Free PMC Article

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