PARPBP is required to suppress inappropriate homologous recombination, thereby playing a central role DNA repair and in the maintenance of genomic stability. PARPBP antagonizes homologous recombination by interfering with the formation of the RAD51-DNA homologous recombination structure. It binds single-strand DNA and poly(A) homopolymers and positively regulate the poly(ADP-ribosyl)ation activity of PARP1; however such function may be indirect.