Details

Autor(en) / Beteiligte

• Rageul, Julie
• Park, Jennifer J
• Jo, Ukhyun
• Weinheimer, Alexandra S
• Vu, Tri T M
• Kim, Hyungjin

Titel

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

Ist Teil von

• Nucleic acids research, 2019-05, Vol.47 (8), p.3996-4010

Ort / Verlag

England

Erscheinungsjahr

2019

Quelle

MEDLINE

Beschreibungen/Notizen

• 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-SDE2Ct, the C-terminal SDE2 fragment bearing an N-terminal Lys residue. Lys-SDE2Ct 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/p97UFD1-NPL4 segregase cooperate to promote phosphorylation-dependent, chromatin-associated Lys-SDE2Ct degradation upon UVC damage. Conversely, cells expressing the degradation-refractory K78V mutant, Val-SDE2Ct, 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.