Mini-chromosome maintenance complex protein 3

Mini-chromosome maintenance complex protein 3(InterPro Protein Domain record)

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Mini-chromosome maintenance complex protein 3

InterPro Protein Domain record

description http://metadb.riken.jp/db/SciNetS_rib124i/prib124u1i

The MCM2-7 complex consists of six closely related proteins that are highly conserved throughout the eukaryotic kingdom. During late mitosis and G1, replication origins are 'licensed' for replication by loading the minichromosome maintenance (MCM) 2-7 proteins pre-replicative complex essential for initiating and elongating replication forks during S phase. The components of the MCM2-7 complex in <taxon tax_id="9606">Homo sapiens</taxon> (Human) (<db_xref db="INTACT" dbkey="EBI-913604"/>) are: .<ul><li> DNA replication licensing factor MCM2, <db_xref db="SWISSPROT" dbkey="P49736"/>, <db_xref db="INTERPRO" dbkey="IPR008045"/> </li><li> DNA replication licensing factor MCM3, <db_xref db="SWISSPROT" dbkey="P25205"/>, <db_xref db="INTERPRO" dbkey="IPR008046"/> </li><li> DNA replication licensing factor MCM4, <db_xref db="SWISSPROT" dbkey="P33991"/>, <db_xref db="INTERPRO" dbkey="IPR008047"/> </li><li> DNA replication licensing factor MCM5, <db_xref db="SWISSPROT" dbkey="P33992"/>, <db_xref db="INTERPRO" dbkey="IPR008048"/> </li><li> DNA replication licensing factor MCM6, <db_xref db="SWISSPROT" dbkey="Q14566"/>, <db_xref db="INTERPRO" dbkey="IPR008049"/> </li><li> DNA replication licensing factor MCM7, <db_xref db="SWISSPROT" dbkey="P33993"/>, <db_xref db="INTERPRO" dbkey="IPR008050"/> </li></ul> Studies in Xenopus eggs have showed the 6 MCM proteins to form hexamers, where each class ispresent in equal stoichiometry [<cite idref="PUB00010317"/>]. The initiation of DNA synthesis ineukaryotes requires the binding of origin recognition complex (ORC) - acomplex of six subunits - to the autonomously replicating sequences (ARS)of replication origins [<cite idref="PUB00010294"/>], the recruitment of CDC6 and binding of the MCMprotein complex to the ARS to form the prereplicative complex (pre-RC) [<cite idref="PUB00010309"/>].DNA synthesis is subsequently initiated by the activation of pre-RC by CDC7and CDC28 protein kinases [<cite idref="PUB00010300"/>].MCM proteins associate with chromatin during G1 phase and dissociate againduring S phase, remaining unbound until the end of mitosis [<cite idref="PUB00010321"/>]. Periodicchromatin association of the MCM complex ensures that DNA synthesis from replication origins is initiated only once during the cell cycle, avoidingover-replication of parts of the genome. Elongation of replication forks away from individual replication origins results in displacement of theMCM-containing complex from chromatin. Budding yeast MCM proteins aretranslocated in and out of the nucleus during each cell cycle. However,fission yeast MCMs, like those in metazoans, are constitutively nuclear.The six classes of MCM protein together share a conserved 200 amino acid residue domain, while sequences within the same class show more extensivesimilarity outside this region. The conserved central domain is similar tothe A motif of the Walker-type NTP-binding domain; it also shares similaritywith ATPase domains of prokaryotic NtrC-related transcription regulators.The ATP-binding motif is thought to mediate ATP-dependent opening of double-stranded DNA at replication origins. In addition to the central region, MCM2,4, 6 and 7 contain a zinc-finger-type motif thought to have a role inmediating protein-protein interactions [<cite idref="PUB00010324"/>]. Moreover, a conserved alpha-helical structure in the C-terminal region has been noted; this comprises aconserved heptad repeat and a putative four-helix bundle. Most of the MCMproteins contain acidic regions, or alternately repeated clusters of acidicand basic residues.Members of the MCM3 class have been isolated from a number of organisms. Human MCM3 was first described as a protein associated with DNA polymerasealpha-primase [<cite idref="PUB00010256"/>], although subsequent analysis failed to show a directinteraction between the them. The gene encoding human MCM3 has beenlocalised to chromosome 6p21.1-p12 [<cite idref="PUB00010364"/>]. In <taxon tax_id="4932">Saccharomyces cerevisiae</taxon> (Baker's yeast), MCM3 is a phospho-protein that exists in multiple isoforms; distinct isoforms can be detected at specific stages of the cell cycle. MCM3 has been implicated in limb development in Xenopus; identification of maternal and zygotic proteins suggests that specific forms may be used at different developmental stages.The MCM3 protein contains a nuclear localisation signal, which is necessary for its translocation into the nucleus.

label http://www.w3.org/2000/01/rdf-schema#label