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SMARCAL1 ubiquitylation controls its association with RPA-coated ssDNA and promotes replication fork stability
Maïlyn Yates1,2, Isabelle Marois1,2, Edlie St-Hilaire3
1Faculty of Sciences, Department of Biology, Université de Sherbrooke, Sherbrooke, Canada.
Plos Biology
|March 19, 2024
Summary
Replication stress causes genomic instability. This study reveals RFWD3 ubiquitin ligase regulates SMARCAL1, preventing excessive DNA cleavage and maintaining fork stability during replication stress.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Replication fork instability leads to genomic instability and disease.
- The ATR kinase pathway and RPA are crucial for the replication stress response.
- RFWD3, a Fanconi anemia ubiquitin ligase, is involved in homologous recombination and replication fork regulation.
Purpose of the Study:
- To identify RFWD3 substrates during replication stress.
- To elucidate the mechanism by which RFWD3 regulates DNA replication fork stability.
Main Methods:
- Proteomics to identify RFWD3 substrates.
- In vitro and in vivo ubiquitylation assays.
- Analysis of DNA replication fork processing and stability.
Main Results:
- RFWD3 directly interacts with and ubiquitylates the SMARCAL1 DNA translocase.
- SMARCAL1 ubiquitylation by RFWD3 disengages SMARCAL1 from RPA, regulating its function.
- RFWD3-mediated SMARCAL1 regulation protects stalled replication forks from excessive MUS81-mediated cleavage.
Conclusions:
- RFWD3-SMARCAL1 ubiquitylation is a novel mechanism for replication fork remodeling.
- This pathway prevents genome instability arising from aberrant fork processing.
- RFWD3 plays a critical role in maintaining genomic integrity under replication stress.
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