title: Claspin recruits Cdc7 kinase for initiation of DNA replication in human cells.
abstract: Claspin transmits replication stress signal from ATR to Chk1 effector kinase as a mediator. It also plays a role in efficient replication fork progression during normal growth. Here we have generated conditional knockout of Claspin and show that Claspin knockout mice are dead by E12.5 and Claspin knockout mouse embryonic fibroblast (MEF) cells show defect in S phase. Using the mutant cell lines, we report the crucial roles of the acidic patch (AP) near the C terminus of Claspin in initiation of DNA replication. Cdc7 kinase binds to AP and this binding is required for phosphorylation of Mcm. AP is involved also in intramolecular interaction with a N-terminal segment, masking the DNA-binding domain and a newly identified PIP motif, and Cdc7-mediated phosphorylation reduces the intramolecular interaction. Our results suggest a new role of Claspin in initiation of DNA replication during normal S phase through the recruitment of Cdc7 that facilitates phosphorylation of Mcm proteins.
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Chi-Chun
authors.initials: CC
authors.lastname: Yang
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Shiori
authors.initials: S
authors.lastname: Yamakawa
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Syuzi
authors.initials: S
authors.lastname: Uno
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Ishii
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Rino
authors.initials: R
authors.lastname: Fukatsu
authors.affiliation: Department of Biology, Faculty of Science, Kyushu University 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Fujisawa
authors.affiliation: Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sakimura
authors.affiliation: Department of Biology, Faculty of Science, Kyushu University 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tsurimoto
authors.affiliation: Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Masai
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000502:physiology; D000071877:Checkpoint Kinase 1 / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C488160:claspin protein, mouse; C068619:CDC7 protein, human; C489403:Cdc7 protein, mouse; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases