As accessory component of the DNA polymerase epsilon complex participates in chromosomal DNA replication. It is required during synthesis of the leading and lagging DNA strands at the replication fork and binds at/or near replication origins and moves along DNA with the replication fork. It has 3'-5' proofreading exonuclease activity that correct errors arising during DNA replication. It is also involved in DNA synthesis during DNA repair. DNA polymerase epsilon is a heterotetramer consisting of POL2, DPB2, DPB3 and DPB4. Phosphorylated in a cell cycle dependent manner during late G1 phase. Phosphorylation may facilitate the interaction with POL2 or the activity of DNA polymerase II. Phosphorylation is independent of DNA replication but dependent upon CDC28 in vivo. Both Ser-141 and Ser-613 are phosphorylated in vivo, but in vitro only Ser-141 is phosphorylated by CDC28. Present with 3110 +/- 251 molecules/cell in log phase SD medium. In eukaryotes there are five DNA polymerases: alpha, beta, gamma, delta, and epsilon which are responsible for different reactions of DNA synthesis. Belongs to the DNA polymerase epsilon subunit B family.