University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA.
Tufts University, Department of Biology, Medford, MA, USA.
Nat Commun. 2024 Aug 21;15(1):7197. doi: 10.1038/s41467-024-51595-0.
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1, SWS1, and SPIDR. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single-molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter Shu complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
依赖于 RAD51 的模板化 DNA 修复发生在同源重组和复制应激期间。RAD51 的活性受到 BRCA2 和 RAD51 同源物的正向调节。Shu 复合物是一种包含 RAD51 同源物的复合物，由 SWSAP1、SWS1 和 SPIDR 组成。我们证明 SWSAP1-SWS1 结合 RAD51，维持 RAD51 丝稳定性，并使链交换成为可能。使用单分子共聚焦荧光显微镜结合光学镊子，我们表明 SWSAP1-SWS1 可对同源重组功能良好的 RAD51 丝进行装饰。我们还发现 SWSAP1-SWS1 增强了 RPA 在 ssDNA 上的扩散。重要的是，我们发现人 sgSWSAP1 和 sgSWS1 敲除细胞对 PARP 和 APE1 的药理学抑制敏感。最后，我们鉴定出 SWSAP1 中的癌症变异会改变 Shu 复合物的形成。总之，我们表明 SWSAP1-SWS1 刺激 RAD51 依赖性高保真修复，可能是一个重要的新癌症治疗靶点。
