Ser/Thr-protein kinase involved in the mitotic exit network (MEN) and required after the metaphase to anaphase cell cycle transition. Phosphorylates CHS2 to regulate its dynamics and chitin synthesis at the division site during cytokinesis. Coordinates septin and actomyosin ring (AMR) functions during cytokinesis through the phosphorylation of HOF1. In complex with MOB1, phosphorylates CDC14 at sites adjacent to its nuclear localization sequence, thereby retaining CDC14 in the cytoplasm. Binds also to SWI5 and CLB2 mRNAs cotranscriptionally to regulate their decay. In the nucleus, the DBF2-MOB1 complex regulates passenger protein localization during anaphase. Mediates sorbic acid stress tolerance through promoting vacuolar H(+)-ATPase function, probably through phosphorylation of VMA1 and VMA2 subunits. 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 regulated by BUB2, CDC15 and CDC5, and is maximal during nuclear division. CDK1 kinase inhibits cellular DBF2-MOB1 kinase activity via phosphorylation of both CDC15 and MOB1. Interacts with MOB1. MOB1-binding is required for a late mitotic event. Localizes on spindle ole body (SPB) for much of the cell cycle and migrates from there to the bud neck in late mitosis. SPB localization during anaphase coincides with activation kinase activity and depends on TEM1 and CDC15. In absence of BUB2, localizes to SPB in cell cycle stages other than anaphase and telophase. Periodically expressed in the cell cycle, with a peak before the onset of budding. Phosphorylation of Ser-374 and Thr-544 by CDC15 is essential for activation of DBF2 kinase activity. Present with 3500 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Truncated N-terminus.