Involved in early stages of the homologous recombination repair (HRR) pathway of double-stranded DNA breaks arising during DNA replication or induced by DNA-damaging agents. Interacts with RAD51D and XRCC3; involved in homologous recombination repair. Interacts with SWSAP1; they form a functional complex involved in homologous recombination repair and stabilize each other. Belongs to the SWS1 family.