MCM proteins are DNA-dependent ATPases required for the initiation of eukaryotic DNA replication [ (PUBMED:1454522) (PUBMED:8265339) (PUBMED:14731643) ]. In eukaryotes there is a family of eight proteins, MCM2 to MCM9. They were first identified in yeast where most of them have a direct role in the initiation of chromosomal DNA replication by interacting directly with autonomously replicating sequences (ARS). They were thus called minichromosome maintenance proteins, MCM proteins [ (PUBMED:8332451) ]. These proteins are evolutionarily related and belong to the AAA+ superfamily. They contain the Mcm family domain, which includes motifs that are required for ATP hydrolysis (such as the Walker A and B, and R-finger motifs). Mcm2-7 forms a hexameric complex [ (PUBMED:9366552) ] in which individual subunits associate with different affinities, and there is a tightly associated core of Mcm4 (Cdc21), Mcm6 (Mis5) and Mcm7 [ (PUBMED:9658174) ]. Mcm2-7 complex is the replicative helicase involved in replication initiation and elongation [ (PUBMED:9305914) ], whereas Mcm8 and Mcm9 from and separate one, conserved among many eukaryotes except yeast and C. elegans. Mcm8/9 complex play a role during replication elongation or recombination, being involved in the repair of double-stranded DNA breaks and DNA interstrand cross-links by homologous recombination. Drosophila is the only organism that has MCM8 without MCM9, involved in meiotic recombination [ (PUBMED:22771115) (PUBMED:30743181) ].
This family is also present in the archebacteria in 1 to 4 copies. Methanocaldococcus jannaschii (Methanococcus jannaschii) has four members, MJ0363, MJ0961, MJ1489 and MJECL13.
Schizosaccharomyces pombe (Fission yeast) MCMs, like those in metazoans, are found in the nucleus throughout the cell cycle. This is in contrast to the Saccharomyces cerevisiae (Baker's yeast) in which MCM proteins move in and out of the nucleus during each cell cycle. The assembly of the MCM complex in S. pombe is required for MCM localisation, ensuring that only intact MCM complexes remain in the nucleus [ (PUBMED:10588642) ].
The AAA team: related ATPases with diverse functions.
Trends Cell Biol. 1998; 8: 65-71
Display abstract
A new family of related ATPases has emerged, characterized by a highly conserved AAA motif. This motif forms a 230-amino-acid domain that contains Walker homology sequences and imparts ATPase activity. Homology between AAA-family members is confined mostly to the AAA domain, although additional homology outside the AAA motif is present among closely related proteins. AAA proteins act in a variety of cellular functions, including cell-cycle regulation, protein degradation, organelle biogenesis and vesicle-mediated protein transport. The AAA domain is required for protein function, but its exact role and the specific activity that it confers on AAA proteins is still unclear. This review describes current understanding of the AAA protein family.
The role of MCM/P1 proteins in the licensing of DNA replication.
Trends Biochem Sci. 1996; 21: 102-6
Display abstract
The DNA replication licensing system ensures that eukaryotic chromosomes replicate precisely once per cell cycle. A central component of the licensing system, RLF-M, has recently been shown to consist of a complex of Mcm/P1 proteins. This result allows us to integrate data about the MCM/P1 family obtained in different eukaryotes, ranging from yeast to man, into a general picture of the way that chromosome replication is controlled.
A common set of conserved motifs in a vast variety of putative nucleic acid-dependent ATPases including MCM proteins involved in the initiation of eukaryotic DNA replication.
Nucleic Acids Res. 1993; 21: 2541-7
Display abstract
A new superfamily of (putative) DNA-dependent ATPases is described that includes the ATPase domains of prokaryotic NtrC-related transcription regulators, MCM proteins involved in the initiation of eukaryotic DNA replication, and a group of uncharacterized bacterial and chloroplast proteins. MCM proteins are shown to contain a modified form of the ATP-binding motif and are predicted to mediate ATP-dependent opening of double-stranded DNA in the replication origins. In a second line of investigation, it is demonstrated that the products of unidentified open reading frames from Marchantia mitochondria and from yeast, and a domain of a baculovirus protein involved in viral DNA replication are related to the superfamily III of DNA and RNA helicases that previously has been known to include only proteins of small viruses. Comparison of the multiple alignments showed that the proteins of the NtrC superfamily and the helicases of superfamily III share three related sequence motifs tightly packed in the ATPase domain that consists of 100-150 amino acid residues. A similar array of conserved motifs is found in the family of DnaA-related ATPases. It is hypothesized that the three large groups of nucleic acid-dependent ATPases have similar structure of the core ATPase domain and have evolved from a common ancestor.
Metabolism (metabolic pathways involving proteins which contain this domain)
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This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with MCM domain which could be assigned to a KEGG orthologous group, and not all proteins containing MCM domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.
