Protein kinase of the mitotic exit network (MEN) essential for late nuclear division in the mitotic cycle. Promotes mitotic exit by phosphorylating DBF2 and directly switching on DBF2 kinase activity. Involved in the localization of DBF2 and DBF20 to the neck which is necessary to undergo cytokinesis. Plays a role in segregation of chromosomes during recovery from spindle checkpoint activation. Required for spindle pole localization of CDK1 and inactivation of CDC2 kinase activity at the end of mitosis. Required for spindle disassembly after meiosis II and plays a role in spore morphogenesis. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Kinase activity is inhibited by phosphorylation and activated by dephosphorylation by CDC14. Homodimer. Interacts with TEM1. Localizes to the spindle pole bodies at late anaphase and translocates to the cytoplasm upon DNA replication stress. Localization to SPBs depends on CDC5 and TEM1 and is inhibited by BUB2. Accumulates at the daughter SPB after anaphase onset when the daughter SPB begins to penetrate the bud neck. Not found in the mother SPD during early anaphase. As anaphase proceeds, continues to accumulate on the daughter SPB and also localizes to the mother SPB. At the end of telophase, a portion of CDC15 localizes at the mother-bud neck. Constitutively expressed. The region between residues 360 and 702 is essential for function and is required for self-association and for binding to spindle pole bodies. The region between residues 751 and 974 is an auto-inhibitory domain which inhibits MEN signaling. Phosphorylation by CDK1 reduces the binding to the mother spindle pole body. The extent of phosphorylation gradually increases during cell-cycle progression until some point during late anaphase/telophase when it is rapidly dephosphorylated by CDC14. Phosphorylation inhibits kinase activity and dephosphorylation by CDC14 activates CDC15. Present with 238 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. It is uncertain whether Met-1 or Met-4 is the initiator.