5'-3' DNA helicase which is recruited to sites of DNA damage and promotes repair of replication-blocking DNA lesions through stimulation of homologous recombination (HR) (PubMed:32640219, PubMed:34552057). Promotes HR by directly stimulating RAD51-mediated strand exchange activity (PubMed:32640219). Not required to load RAD51 at sites of DNA damage but promotes recombinational repair after RAD51 recruitment (PubMed:32640219). Also promotes HR by positively regulating EXO1-mediated DNA end resection of double-strand breaks (PubMed:34552057). Required for recruitment of replication protein RPA2 to DNA damage sites (PubMed:34552057). Promotes the initiation of the G2/M checkpoint but not its maintenance (PubMed:34552057). Catalyzes Holliday junction branch migration and dissociation of D-loops and DNA flaps (PubMed:32640219). {ECO:0000269|PubMed:32640219, ECO:0000269|PubMed:34552057}. This is the function of Ensembl gene identifier ENSG00000138658 (ZGRF1, zinc finger GRF-type containing 1).