Control of mitotic exit by PP2A regulation of Cdc25C and Cdk1.

ABSTRACT: Inactivation of maturation-promoting factor [(MPF) Cdk1/Cyclin B] is a key event in the exit from mitosis. Although degradation of Cyclin B is important for MPF inactivation, recent studies indicate that Cdk1 phosphorylation and inactivation occur before Cyclin B degradation and, therefore, also may be important steps in the exit from mitosis. Cdk1 activity is controlled by the Cdc25C phosphatase, which is turned on at the G(2)/M transition to catalyze Cdk1 activation. PP2A:B56delta is a negative regulator of Cdc25C during interphase. We show here that PP2A:B56delta also regulates Cdc25C at mitosis. Failure of PP2A:B56delta to dephosphorylate Cdc25C at mitosis results in prolonged hyperphosphorylation and activation of Cdc25C, causing persistent dephosphorylation and, hence, activation of

SUBMITTER: Forester CM 

PROVIDER: S-EPMC2148389 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature