cdc2 protein kinase: structure-function relationships.
Activation of the cdc2 kinase in the cell cycle occurs upon binding to a regulatory subunit called cyclin. Cyclin A associates with both Cdc2 and its homologue Cdk2. The two complexes appear in S phase but cyclin A/Cdk2 is activated earlier than cyclin A/Cdc2. Several regions in Cdc2 are involved in binding cyclins A and B. Phosphorylation of cyclin/Cdk complexes ensures that the kinase activity peaks at a specific time in the cell cycle. Phosphorylation of Thr161 in Cdc2 is required for strong cyclin binding and kinase activity in vitro; its dephosphorylation is necessary for cells to exit mitosis. We have identified a novel 'Activating factor' that stimulates binding between cyclin and Cdc2 by inducing phosphorylation of Cdc2 on Thr161. We propose that Thr161 is targeted by an additional cell cycle regulatory pathway.
Marcote
M J
MJ
Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Pagano
M
M
Draetta
G
G
D016203:CDC2 Protein Kinase / Q000737:chemistry* / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D016213:Cyclins / Q000378:metabolism / Q000502:physiology; D006801:Humans; D013329:Structure-Activity Relationship
D016213:Cyclins; D016203:CDC2 Protein Kinase