The phosphatase Cdc14 triggers mitotic exit by reversal of CDK-dependent phosphorylation

Exit from mitosis requires the inactivation of mitotic cyclin-dependent kin ases (CDKs) by an unknown mechanism. We show that the Gdc14 phosphatase tri ggers mitotic exit: by three parallel mechanisms, each of which inhibits Cd k activity. Cdc14 dephosphorylates Sic1,a Cdk inhibitor, and Swi5, a transc ription factor for SIC1, and induces degradation of mitotic cyclins, likely by dephosphorylating the activator of mitotic cyclin degradation, Cdh1/Hct 1. Feedback between these pathways may lead to precipitous collapse of mito tic CDK activity and help coordinate exit from mitosis.