NCIt definition : The MCM proteins are essential replication initiation factors. The best known among
them are a family of six structurally related proteins, MCM2-7, which are evolutionally
conserved in all eukaryotes. The MCM2-7 proteins form a hexameric complex. This complex
is a key component of the prereplication complex that assembles at replication origins
during early G1 phase. The MCM2-7 proteins may be involved not only in the initiation
but also in the elongation of DNA replication. Orchestration of the functional interactions
between the MCM2-7 proteins and other components of the prereplication complex by
cell cycle-dependent protein kinases results in initiation of DNA synthesis once every
cell cycle. (from PMID 10872463 and NCI);