Has a role in the initiation of DNA replication. Required at S-phase checkpoint. Required for the association of PSF1 with origins. Also required for the proper activation of RAD53 in response to DNA damage and replication blocks. Multicopy suppressor of DPB2 mutation. Overexpression restores the growth defect conferred by POL2 mutation. Interacts with SLD2. Present with 540 molecules/cell in log phase SD medium.