The structural basis for MCM2–7 helicase activation by GINS and Cdc45

Costa, Alessandro; Ilves, Ivar; Tamberg, Nele; Petojevic, Tatjana; Nogales, Eva; Botchan, Michael R.; Berger, James M.

doi:10.1038/nsmb.2004

Cited by 294 publications

(408 citation statements)

References 59 publications

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“…Binding of purified Mcm2 -7 to ssDNA circles suggests that the interface between Mcm2 and Mcm5 acts as a "gate" to the central channel . EM studies of purified Drosophila Mcm2 -7 support this conclusion (Costa et al 2011). Although ATP binding is believed to close the Mcm2/5 gate, it is likely that some combination of Cdt1 binding and Cdc6 ATP hydrolysis modulates Mcm2 -7 ring opening during helicase loading.…”

Section: Mcm2 -7 Gate Function and Implications For Loadingsupporting

confidence: 48%

“…The eukaryotic replicative DNA helicase is the Mcm2 -7complex.EachMcm2 -7complexcon-tains one copy of the six essential and related Although high-resolution structural data are not available, electron microscopy (EM) and subunit interaction studies indicate that the Mcm2 -7 proteins interact in a defined order Yu et al 2004;) to form either a ring ) or a gapped ring (Costa et al 2011) with a positively charged central channel (Fig. 2).…”

Section: Mcm2 -7 Helicasementioning

confidence: 99%

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Helicase Loading at Chromosomal Origins of Replication

Bell

Kaguni

2013

Cold Spring Harbor Perspectives in Biology

114

107

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Loading of the replicative DNA helicase at origins of replication is of central importance in DNA replication. As the first of the replication fork proteins assemble at chromosomal origins of replication, the loaded helicase is required for the recruitment of the rest of the replication machinery. In this work, we review the current knowledge of helicase loading at Escherichia coli and eukaryotic origins of replication. In each case, this process requires both an origin recognition protein as well as one or more additional proteins. Comparison of these events shows intriguing similarities that suggest a similar underlying mechanism, as well as critical differences that likely reflect the distinct processes that regulate helicase loading in bacterial and eukaryotic cells.

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Section: Mcm2 -7 Gate Function and Implications For Loadingsupporting

confidence: 48%

Section: Mcm2 -7 Helicasementioning

confidence: 99%

Helicase Loading at Chromosomal Origins of Replication

Bell

Kaguni

2013

Cold Spring Harbor Perspectives in Biology

114

107

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“…This is supported by the adaptation of yPold3 for Okazaki fragment processing and also by recent advances in the study of the GINS complex, which is a component of the eukaryotic initiation helicase, the CMG complex [MacNeill, 2010;Bermudez et al, 2011;Costa et al, 2011;Kang et al, 2012]. The recruitment of Pol a and Pol e to the GINS complex is a key step in initiation of DNA replication, and the association of Pol e with the GINS complex provides for a separate structural unit associated with ongoing leading strand synthesis [Seki et al, 2006;Chang et al, 2007].…”

Section: Role Of Pol D At the Replication Forkmentioning

confidence: 93%

Regulation of human DNA polymerase delta in the cellular responses to DNA damage

Lee

Zhang

Lin

et al. 2012

Environ and Mol Mutagen

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The p12 subunit of polymerase delta (Pol d) is degraded in response to DNA damage induced by UV, alkylating agents, oxidative, and replication stresses. This leads to the conversion of the Pol d4 holoenzyme to the heterotrimer, Pol d3. We review studies that establish that Pol d3 formation is an event that could have a major impact on cellular processes in genomic surveillance, DNA replication, and DNA repair. p12 degradation is dependent on the apical ataxia telangiectasia and Rad3 related (ATR) kinase and is mediated by the ubiquitin-proteasome system. Pol d3 exhibits properties of an ''antimutator'' polymerase, suggesting that it could contribute to an increased surveillance against mutagenesis, for example, when Pol d carries out bypass synthesis past small base lesions that engage in spurious base pairing. Chromatin immunoprecipitation analysis and examination of the spatiotemporal recruitment of Pol d to sites of DNA damage show that Pol d3 is the primary form of Pol d associated with cyclobutane pyrimidine dimer lesions and therefore should be considered as the operative form of Pol d engaged in DNA repair. We propose a model for the switching of Pol d with translesion polymerases, incorporating the salient features of the recently determined structure of monoubiquitinated proliferating cell nuclear antigen and emphasizing the role of Pol d3. Because of the critical role of Pol d activity in DNA replication and repair, the formation of Pol d3 in response to DNA damage opens the prospect that pleiotropic effects may ensue. This opens the horizons for future exploration of how this novel response to DNA damage contributes to genomic stability. Environ. Mol. Mutagen. 53:683-698, 2012. V V C 2012 Wiley Periodicals, Inc.

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“…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)(15)(16). This breach has been proposed to act as a gate by which DNA enters into the motor interior.…”

mentioning

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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The structural basis for MCM2–7 helicase activation by GINS and Cdc45

Cited by 294 publications

References 59 publications

Helicase Loading at Chromosomal Origins of Replication

Helicase Loading at Chromosomal Origins of Replication

Regulation of human DNA polymerase delta in the cellular responses to DNA damage

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

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