Accessory component of the DNA polymerase epsilon complex (PubMed:10801849). Participates in DNA repair and in chromosomal DNA replication (By similarity). Forms a complex with CHRAC1 and binds naked DNA, which is then incorporated into chromatin, aided by the nucleosome-remodeling activity of ISWI/SNF2H and ACF1 (PubMed:10801849). Does not enhance nucleosome sliding activity of the ACF-5 ISWI chromatin remodeling complex (PubMed:14759371). 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 POLE4 is a prerequisite for further binding with POLE and POLE2. Heterodimer with CHRAC1; binds to DNA (PubMed:10880450). Component of the CHRAC ISWI chromatin remodeling complex at least composed of SMARCA5/SNF2H, BAZ1A/ACF1, CHRAC1 and POLE3; the complex preferentially binds DNA through the CHRAC1-POLE3 heterodimer and possesses ATP-dependent nucleosome-remodeling activity (PubMed:10880450). Within the complex, the heterodimer with CHRAC1 interacts with SMARCA5/SNF2H; the interaction is direct and enhances nucleosome sliding activity by the SMARCA5/SNF2H and BAZ1A/ACF1 interaction (PubMed:10880450, PubMed:14759371). Within the complex, the heterodimer with CHRAC1 interacts with BAZ1A/ACF1; the interactions are direct (PubMed:10880450, PubMed:12434153, PubMed:14759371). Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas.