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Published May 7, 2019 | Supplemental Material + Published
Journal Article Open

Conditional degradation of SDE2 by the Arg/N-End rule pathway regulates stress response at replication forks

Abstract

Multiple pathways counteract DNA replication stress to prevent genomic instability and tumorigenesis. The recently identified human SDE2 is a genome surveillance protein regulated by PCNA, a DNA clamp and processivity factor at replication forks. Here, we show that SDE2 cleavage after its ubiquitin-like domain generates Lys-SDE2^(Ct), the C-terminal SDE2 fragment bearing an N-terminal Lys residue. Lys-SDE2^(Ct) constitutes a short-lived physiological substrate of the Arg/N-end rule proteolytic pathway, in which UBR1 and UBR2 ubiquitin ligases mediate the degradation. The Arg/N-end rule and VCP/p97^(UFD1-NPL4) segregase cooperate to promote phosphorylation-dependent, chromatin-associated Lys-SDE2^(Ct) degradation upon UVC damage. Conversely, cells expressing the degradation-refractory K78V mutant, Val-SDE2^(Ct), fail to induce RPA phosphorylation and single-stranded DNA formation, leading to defects in PCNA-dependent DNA damage bypass and stalled fork recovery. Together, our study elucidates a previously unappreciated axis connecting the Arg/N-end rule and the p97-mediated proteolysis with the replication stress response, working together to preserve replication fork integrity.

Additional Information

© The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: 03 January 2019; Accepted: 24 January 2019; Published: 30 January 2019. We thank Dr. Alexander Varshavsky (Caltech) for his insightful discussion and reagents. We thank Dr. Daniel Durocher (The Lunenfeld-Tanenbaum Research Institute) for a cell line and Dr. Orlando Schärer (UNIST, Korea) for critically reading the manuscript. Funding: National Institutes of Health [CA218132]; American Cancer Society [RSG-18-037-01-DMC]; Concern Foundation; Carol M. Baldwin Breast Cancer Research Award; and Startup fund from the Research Foundation and the Cancer Center at Stony Brook University (to H.K.). Funding for open access charge: American Cancer Society. Conflict of interest statement. None declared.

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Supplemental Material - gkz054_supplemental_files.pdf

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Additional details

Created:
August 19, 2023
Modified:
October 20, 2023