PolD2 (DNA polymerase delta, subunit 2) is an auxiliary subunit of the eukaryotic DNA polymerase delta (PolD) complex thought to play a regulatory role and to serve as a scaffold for PolD assembly by interacting simultaneously with all of the other three subunits. PolD2 is catalytically inactive and lacks the active site residues required for phosphoesterase activity in other members of this superfamily. PolD2 is also involved in the recruitment of several proteins regulating DNA metabolism, including p21, PDIP1, PDIP38, PDIP46, and WRN. Human PolD consists of four subunits: p125 (PolD1), p50 (PolD2), p66(PolD3), and p12(PolD4). PolD is one of three major replicases in eukaryotes. PolD also plays an essential role in translesion DNA synthesis, homologous recombination, and DNA repair. Within the PolD complex, PolD2 tightly associates with PolD3 [, ]. PolD2 belongs to the metallophosphatase (MPP) superfamily.
