Accessory component of the DNA polymerase epsilon complex (PubMed:10801849). Participates in DNA repair and in chromosomal DNA replication (By similarity). Component of the DNA polymerase epsilon complex consisting of four subunits: the catalytic subunit POLE and the accessory subunits POLE2, POLE3 and POLE4. Interaction with POLE3 is a prerequisite for further binding with POLE and POLE2.