RNF185 orchestrates replication fork restart and homologous recombination through temporal RPA1 ubiquitination...

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Replication protein A (RPA) is essential for DNA replication, repair, and recombination.
• Mechanisms controlling RPA's dynamic engagement and release at DNA damage sites remain unclear.
• Understanding RPA regulation is critical for addressing replication stress and DNA repair pathways.

Purpose of the Study:

• To identify key regulators of RPA dynamics during DNA damage response.
• To elucidate the role of E3 ligases in orchestrating RPA ubiquitination.
• To investigate how RNF185 influences homologous recombination and replication fork restart.

Main Methods:

• Identification of RNF185 as a novel E3 ligase targeting RPA1.
• Analysis of RPA1 ubiquitination patterns (K6/K63-linked vs. K48-linked).
• Investigation of RNF185 phosphorylation, nuclear translocation, and interactions with NUP88 and OTUB1.
• Assessment of RNF185's impact on DNA repair, replication fork stability, and cellular sensitivity to DNA damaging agents.

Main Results:

• RNF185 orchestrates distinct RPA1 ubiquitination patterns crucial for DNA repair.
• RNF185 promotes early K6/K63-linked ubiquitination for RPA1 stabilization and fork restart.
• RNF185 facilitates later K48-linked ubiquitination, promoting RPA1 degradation and removal.
• Loss of RNF185 impairs homologous recombination, destabilizes replication forks, and increases sensitivity to genotoxic stress.

Conclusions:

• RNF185 is a critical regulator of RPA turnover and DNA damage response.
• RNF185's dual ubiquitination control ensures timely RPA engagement and release.
• RNF185 deficiency compromises tumor cell response to radiotherapy and chemotherapy.
• RNF185 represents a potential therapeutic target for enhancing cancer treatment efficacy.