Required to suppress inappropriate homologous recombination, thereby playing a central role DNA repair and in the maintenance of genomic stability. Antagonizes homologous recombination by interfering with the formation of the RAD51-DNA homologous recombination structure. Binds single-strand DNA and poly(A) homopolymers. Positively regulate the poly(ADP-ribosyl)ation activity of PARP1; however such function may be indirect (By similarity). Interacts with RAD51 and PCNA. Interacts with PARP1 (By similarity). Interacts with TASOR (By similarity). Localizes to chromatin in response to S phase arrest but not in mitosis. Targeted to chromatin via its interaction with PCNA (By similarity). Belongs to the PARI family.