Inhibition of Mcm4,6,7 helicase activity by phosphorylation with cyclin A/Cdk2.
A strong body of evidence indicates that cyclin-dependent protein kinases are required not only for the initiation of DNA replication but also for preventing over-replication in eukaryotic cells. Mcm proteins are one of the components of the replication licensing system that permits only a single round of DNA replication per cell cycle. It has been reported that Mcm proteins are phosphorylated by the cyclin-dependent kinases in vivo, suggesting that these two factors are cooperatively involved in the regulation of DNA replication. Our group has reported that a 600-kDa Mcm4,6,7 complex has a DNA helicase activity that is probably necessary for the initiation of DNA replication. Here, we examined the in vitro phosphorylation of the Mcm complexes with cyclin A/Cdk2 to understand the interplay between Mcm proteins and cyclin-dependent kinases. The cyclin A/Cdk2 mainly phosphorylated the amino-terminal region of Mcm4 in the Mcm4,6,7 complex. The phosphorylation was associated with the inactivation of its DNA helicase activity. These results raise the possibility that the inactivation of Mcm4,6,7 helicase activity by Cdk2 is a part of the system for regulating DNA replication.
Ishimi
Y
Y
Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan. yukio@libra.m-kagaku.co.jp
Komamura-Kohno
Y
Y
You
Z
Z
Omori
A
A
Kitagawa
M
M
D000818:Animals; D042846:CDC2-CDC28 Kinases; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004265:DNA Helicases / Q000037:antagonists & inhibitors*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000494:pharmacology; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D009154:Mutation; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D025521:Tumor Suppressor Proteins
C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D004265:DNA Helicases; C092802:MCM4 protein, S cerevisiae; C491207:MCM6 protein, S cerevisiae; C103258:MCM6 protein, human; C491088:MCM7 protein, S cerevisiae; C101624:MCM7 protein, human; C491205:Mcm6 protein, mouse; C491086:Mcm7 protein, mouse; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7