title: ATP-dependent activation of p21WAF1/CIP1-associated Cdk2 by Cdc6.
abstract: When cells progressing in mid-S phase are damaged with a base-modifying chemical, they arrest in S phase long after the CHK1 checkpoint signal fades out, partly because of p53-mediated long-lasting induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1). We have recently found that enforced expression of Cdc6, the assembler of prereplicative complexes, markedly advances recovery from the prolonged S-phase arrest and reactivation of Cdk2 despite the presence of a high level of induced p21. Here, we report that Cdc6 protein can activate p21-associated Cdk2 in an ATP-dependent manner in vitro. Consistently, Cdc6 mutated for ATPase or a putative cyclin binding motif is no longer able to activate the Cdk2 in vitro or promote reinitiation of S-phase progression and reactivation of Cdk2 in vivo. These results reveal the never anticipated function of Cdc6 and redefine its role in the control of S-phase progression in mammalian cells.
authors: Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Qiuming
authors: Q
authors: Kan
authors: Shigeki
authors: S
authors: Jinno
authors: Hanako
authors: H
authors: Yamamoto
authors: Kohei
authors: K
authors: Kobayashi
authors: Hiroto
authors: H
authors: Okayama
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D020816:Amino Acid Motifs; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D051379:Mice; D009154:Mutation / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D016196:S Phase / Q000187:drug effects
chemical_list: C528180:Cdc6 protein, rat; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D000255:Adenosine Triphosphate; D008741:Methyl Methanesulfonate; D051357:Cyclin-Dependent Kinase 2; D000251:Adenosine Triphosphatases