Cdc15 Background Information Exit from mitosis is regulated by the mitotic exit network, which includes a GTPase (Tem1) and various kinases (Cdc15, Cdc5, Dbf2, and Dbf20). Inactivation of mitotic cyclin-dependent kinases (Cdks) is required for cells to exit mitosis. Cdc15 protein influences the organization of lipid rafts at the cleavage site for cytokinesis. Cdc15 is phosphorylated at multiple Cdk-consensus sites during most of the cell cycle, yet is transiently dephosphorylated in late mitosis. Although phosphorylation appears to have no effect on Cdc15 kinase activity, phosphorylation does inhibit Cdc15 from mediating mitotic exit. Cdc15 serves both as an activator and substrate of Cdc14.