Phosphorylation of Mcm2 by Cdc7 Promotes Pre-replication Complex Assembly during Cell-Cycle Re-entry

Chuang, Li-Chiou; Teixeira, Leonardo K.; Wohlschlegel, James A.; Henze, Martha; Yates, John R.; Méndez, Juan Pablo; Reed, Steven I.

doi:10.1016/j.molcel.2009.06.014

Cited by 63 publications

(66 citation statements)

References 39 publications

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“…EcuMCM2-7 lacks the large, unstructured, and posttranslationally modified regions that help regulate loading and activation in other eukaryotic helicases (Fig. S1) (10,32), and it could serve as a model system for probing basic structure/activity relationships of eukaryotic MCMs. EcuMCM2-7 was isolated as a stable assembly, with ATPase and DNA binding properties comparable with those properties of other MCM proteins ( Fig.…”

Section: Discussionmentioning

confidence: 99%

ATP-dependent conformational dynamics underlie the functional asymmetry of the replicative helicase from a minimalist eukaryote

Lyubimov

Costa

Bleichert

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The heterohexameric minichromosome maintenance (MCM2-7) complex is an ATPase that serves as the central replicative helicase in eukaryotes. During initiation, the ring-shaped MCM2-7 particle is thought to open to facilitate loading onto DNA. The conformational state accessed during ring opening, the interplay between ATP binding and MCM2-7 architecture, and the use of these events in the regulation of DNA unwinding are poorly understood. To address these issues in isolation from the regulatory complexity of existing eukaryotic model systems, we investigated the structure/function relationships of a naturally minimized MCM2-7 complex from the microsporidian parasite Encephalitozoon cuniculi. Electron microscopy and small-angle X-ray scattering studies show that, in the absence of ATP, MCM2-7 spontaneously adopts a lefthanded, open-ring structure. Nucleotide binding does not promote ring closure but does cause the particle to constrict in a two-step process that correlates with the filling of high-and low-affinity ATPase sites. Our findings support the idea that an open ring forms the default conformational state of the isolated MCM2-7 complex, and they provide a structural framework for understanding the multiphasic ATPase kinetics observed in different MCM2-7 systems. T he replisome is a large macromolecular machine that coordinates the activity of multiple functional components to ensure the faithful and timely duplication of DNA. Replisome progression is powered, in part, by hexameric helicases, which unwind parental duplexes to provide template strands for DNA synthesis. Because of their ring-shaped structure, the encirclement of single-or double-stranded DNA by replicative helicases is topologically restricted. This restriction can be overcome by either the direct assembly of the motor onto DNA (1-3) or dedicated loading factors that assist ring opening (1, 4, 5). How and why different hexameric helicases use a particular strategy are long-standing questions.The eukaryotic replicative helicase is composed of six distinct but homologous ATPases associated with various cellular activities (AAA+) subunits, collectively termed the minichromosome maintenance (MCM2-7) complex (6, 7). During the G1-phase of the cell cycle, MCM2-7 heterohexamers are loaded onto DNA by the origin recognition complex together with the Cdc6 and Cdt1 proteins (8, 9). As cells enter S-phase, MCM2-7 is activated through phosphorylation of Mcm2, Mcm4, and Mcm6 by the Dbf4-dependent Cdc7 kinase (10, 11) and the chaperoned association of two accessory factors, Cdc45 and GINS (11). The resultant Cdc45-MCM-GINS (CMG) complex then translocates in the 3′→5′ direction along the leading strand, displacing the lagging strand to facilitate DNA unwinding (12, 13).Studies of both Saccharomyces cerevisiae (Sce) and Drosophila melanogaster (Dme) MCM2-7 indicated that the helicase ring spontaneously opens between the Mcm2 and Mcm5 subunits (14-16). This breach has been proposed to act as a gate by which DNA enters into the motor interior. What triggers t...

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Section: Discussionmentioning

confidence: 99%

ATP-dependent conformational dynamics underlie the functional asymmetry of the replicative helicase from a minimalist eukaryote

Lyubimov

Costa

Bleichert

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Clearly there is still much to learn regarding how the MCM2-7 helicase is regulated by Cdc7 phosphorylation in human cells, and indeed a recent study argues that Cdc7 might promote the assembly of the MCM2-7 complex onto chromatin during re-entry into the cell cycle from quiescence (Chuang et al 2009). Nevertheless, it now seems very likely that the mechanism by which Cdc7 promotes activation of the MCM2-7 helicase and the initiation of chromosome replication will be fundamentally similar in all eukaryotes.…”

Section: Sld2 and Sld3 Are The Major Targets For Cdk During The Initimentioning

confidence: 99%

How do Cdc7 and cyclin-dependent kinases trigger the initiation of chromosome replication in eukaryotic cells?

Labib¹

2010

Genes Dev.

318

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Chromosome replication occurs precisely once during the cell cycle of almost all eukaryotic cells, and is a highly complex process that is still understood relatively poorly. Two conserved kinases called Cdc7 (cell division cycle 7) and cyclin-dependent kinase (CDK) are required to establish replication forks during the initiation of chromosome replication, and a key feature of this process is the activation of the replicative DNA helicase in situ at each origin of DNA replication. A series of recent studies has shed new light on the targets of Cdc7 and CDK, indicating that chromosome replication probably initiates by a fundamentally similar mechanism in all eukaryotes.

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“…The phosphorylation of S222 on CDCA5 is shown to be caused by CDK1 during mitosis and involed in controling the release of CDCA5 from chromosomes (50). The phosphorylation of MCM2 on serine 27 is proven to be caused by Cdc7/Dbf4 in G1/S transition and coincides with the initiation of DNA replication (51). If RIP3 phosphorylates MCM2 on this site, RIP3 could promote DNA synthesis.…”

Section: Implications Of Rip3-dependent Protein Phosphorylations-tomentioning

confidence: 99%

Investigation of Receptor interacting protein (RIP3)-dependent Protein Phosphorylation by Quantitative Phosphoproteomics

Tian

et al. 2012

Molecular & Cellular Proteomics

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MEFs than in RIP3؊/؊ cells. Many of the RIP3 regulated phosphoproteins from the macrophages and MEF cells are functionally associated with the cell cycle; the rest, however, appear to have diverse functions in that a number of metabolism related proteins were phosphorylated in macrophages and development related phosphoproteins were induced in MEFs. The results of our phosphoproteomic analysis suggest that RIP3 might function beyond necrosis and that cell type specific function of RIP3

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Phosphorylation of Mcm2 by Cdc7 Promotes Pre-replication Complex Assembly during Cell-Cycle Re-entry

Cited by 63 publications

References 39 publications

ATP-dependent conformational dynamics underlie the functional asymmetry of the replicative helicase from a minimalist eukaryote

ATP-dependent conformational dynamics underlie the functional asymmetry of the replicative helicase from a minimalist eukaryote

How do Cdc7 and cyclin-dependent kinases trigger the initiation of chromosome replication in eukaryotic cells?

Investigation of Receptor interacting protein (RIP3)-dependent Protein Phosphorylation by Quantitative Phosphoproteomics

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