Cdc6 protein activates p27KIP1-bound Cdk2 protein only after the bound p27 protein undergoes C-terminal phosphorylation.
In mammalian cells Cdk2 activity during the G(1)-S transition is mainly controlled by p27(KIP1). Although the amount and subcellular localization of p27 influence Cdk2 activity, how Cdk2 activity is regulated during this phase transition still remains virtually unknown. Here we report an entirely new mechanism for this regulation. Cdc6 the AAA+ ATPase, known to assemble prereplicative complexes on chromosomal replication origins and activate p21(CIP1)-bound Cdk2, also activated p27-bound Cdk2 in its ATPase and cyclin binding motif-dependent manner but only after the p27 bound to the Cdk2 was phosphorylated at the C terminus. ROCK, which mediates a signal for cell anchorage to the extracellular matrix and activates the mTORC1 cascade as well as controls cytoskeleton assembly, was partly responsible for C-terminal phosphorylation of the p27. In vitro reconstitution demonstrated ROCK (Rho-associated kinase)-mediated phosphorylation of Cdk2-bound p27 at the C terminus and subsequent activation of the Cdk2 by Cdc6.
Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Baasanjav
B
Uranbileg
Hanako
H
Yamamoto
Jung-ha
JH
Park
Atish R
AR
Mohanty
Shiho
S
Arakawa-Takeuchi
Shigeki
S
Jinno
Hiroto
H
Okayama
D019943:Amino Acid Substitution / Q000502:physiology; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D056743:Cyclin D3 / Q000235:genetics / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000737:chemistry / Q000378:metabolism*; D003599:Cytoskeleton / Q000502:physiology; D004789:Enzyme Activation / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D051379:Mice; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D000076205:Ras Homolog Enriched in Brain Protein; D051381:Rats; D013912:Threonine / Q000378:metabolism; D054460:rho-Associated Kinases / Q000378:metabolism
C103706:CDC6 protein, human; C534697:Ccnd3 protein, mouse; D018797:Cell Cycle Proteins; D056743:Cyclin D3; D009479:Neuropeptides; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D000076205:Ras Homolog Enriched in Brain Protein; C087693:Rheb protein, rat; D050760:Cyclin-Dependent Kinase Inhibitor p27; D013912:Threonine; D054460:rho-Associated Kinases; C495892:Cdk2 protein, rat; D051357:Cyclin-Dependent Kinase 2; D020559:Monomeric GTP-Binding Proteins