Acts as component of the MCM2-7 complex (MCM complex) which is the putative replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity. Required for the entry in S phase and for cell division. Plays a role in terminally differentiated hair cells development of the cochlea and induces cells apoptosis. Component of the MCM2-7 complex (PubMed:9305914, PubMed:16899510, PubMed:17296731). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:9305914, PubMed:16899510, PubMed:17296731). Interacts with DBF4 (By similarity). Interacts with KAT7 (PubMed:16387653). May interact with MCM10 (PubMed:11095689). Component of the replisome complex composed of at least DONSON, MCM2, MCM7, PCNA and TICRR (PubMed:28191891). Component of the CMG helicase complex, composed of the MCM2-7 complex, the GINS complex and CDC45 (By similarity). Forms a co-chaperone complex with DNAJC9 and histone H3.3-H4 heterodimers (PubMed:33857403). Within the complex, interacts (via N-terminus) with DNAJC9 (via C-terminus); the interaction is histone-dependent (PubMed:33857403). Interacts with histones H3.1 and H3.3 (PubMed:33857403). Associated with chromatin before the formation of nuclei and detaches from it as DNA replication progresses. Phosphorylated on Ser-108 by ATR in proliferating cells. Ser-108 proliferation is increased by genotoxic agents. Ser-40 is mediated by the CDC7-DBF4 and CDC7-DBF4B complexes, while Ser-53 phosphorylation is only mediated by the CDC7-DBF4 complex. Phosphorylation by the CDC7-DBF4 complex during G1/S phase is required for the initiation of DNA replication. The disease is caused by variants affecting the gene represented in this entry. Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. Specifically a MCM467 subcomplex is shown to have in vitro helicase activity which is inhibited by the MCM2 subunit. The MCM2-7 hexamer is the proposed physiological active complex. Belongs to the MCM family. Extended N-terminus. Truncated N-terminus. Extended N-terminus.