title: Requirements for Cdk7 in the assembly of Cdk1/cyclin B and activation of Cdk2 revealed by chemical genetics in human cells.
abstract: Cell division is controlled by cyclin-dependent kinases (CDKs). In metazoans, S phase onset coincides with activation of Cdk2, whereas Cdk1 triggers mitosis. Both Cdk1 and -2 require cyclin binding and T loop phosphorylation for full activity. The only known CDK-activating kinase (CAK) in metazoans is Cdk7, which is also part of the transcription machinery. To test the requirements for Cdk7 in vivo, we replaced wild-type Cdk7 with a version sensitive to bulky ATP analogs in human cancer cells. Selective inhibition of Cdk7 in G1 prevents activation (but not formation) of Cdk2/cyclin complexes and delays S phase. Inhibiting Cdk7 in G2 blocks entry to mitosis and disrupts Cdk1/cyclin B complex assembly, indicating that the two steps of Cdk1 activation-cyclin binding and T loop phosphorylation-are mutually dependent. Therefore, by combining chemical genetics and homologous gene replacement in somatic cells, we reveal different modes of CDK activation by Cdk7 at two distinct execution points in the cell cycle.
authors: Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
authors: Stéphane
authors: S
authors: Larochelle
authors: Karl A
authors: KA
authors: Merrick
authors: Marie-Emilie
authors: ME
authors: Terret
authors: Lara
authors: L
authors: Wohlbold
authors: Nora M
authors: NM
authors: Barboza
authors: Chao
authors: C
authors: Zhang
authors: Kevan M
authors: KM
authors: Shokat
authors: Prasad V
authors: PV
authors: Jallepalli
authors: Robert P
authors: RP
authors: Fisher
mesh_terms: D016203:CDC2 Protein Kinase / Q000235:genetics*; D002453:Cell Cycle; D002455:Cell Division; D002470:Cell Survival; D019926:Cyclin B / Q000235:genetics*; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D008938:Mitosis; D016196:S Phase; D000095043:Cyclin-Dependent Kinase-Activating Kinase
chemical_list: D019926:Cyclin B; D016203:CDC2 Protein Kinase; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase; C000722416:CDK7 protein, human