MCM4
Description
The MCM4 (minichromosome maintenance complex component 4) is a protein-coding gene located on chromosome 8.
MCM4 is a highly conserved protein involved in the initiation of eukaryotic genome replication. It forms a hexameric complex with other MCM proteins, which is a key component of the pre-replication complex (pre-RC). This complex may be involved in the formation of replication forks and the recruitment of other DNA replication-related proteins. The MCM complex, including MCM4, MCM2, MCM6, and MCM7, exhibits DNA helicase activity, acting as a DNA unwinding enzyme. Phosphorylation of MCM4 by CDC2 kinase reduces its DNA helicase activity and chromatin binding. MCM4 is located on chromosome 8, head-to-head next to PRKDC/DNA-PK, a DNA-activated protein kinase involved in DNA double-strand break repair. Alternative splicing generates transcript variants encoding the same protein.
MCM4 is a key component of the MCM2-7 complex (MCM complex), the replicative helicase essential for "once per cell cycle" DNA replication initiation and elongation in eukaryotic cells. It is also a core component of the CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication and around which the replisome is built. The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits, with a conserved arginine finger motif contributing to the ATP-binding site of the adjacent subunit. While the six ATPase active sites are likely to contribute differentially to the complex helicase activity, their precise roles are still under investigation.
MCM4 is also known as CDC21, CDC54, IMD54, NKCD, NKGCD, P1-CDC21, hCdc21.
