Regulator of DNA replication. Promotes initiation of chromosomal DNA replication by mediating topbp1- and cdk2-dependent recruitment of cdc45l onto replication origins. Interacts with topbp1. Interacts with Cdc45l and the kinase cdk2-cyclin-E (the interaction is direct). Associates with chromatin during pre-replication complex (pre-RC) formation following interaction with topbp1. Expressed in most tissues. Enriched in proliferating cells from skin and gut. Highly phosphorylated by cdk2; stimulates initiation of DNA replication. Belongs to the GEMC1 family.