May play an important role in mitotic control by altering cellular location, degree of phosphorylation and kinase activity. Abundant expression accelerates the exit when cells are in M-phase and also delays the entry into mitosis when cells are in G2. Phosphorylates prp2 in vitro and so may have a role in co-ordinating pre-mRNA splicing with the progression of the cell division cycle. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Enriched in the nucleus in mitotically arrested mutant and wild-type mitotic cells but cytoplasmic enriched in cells at other cell-cycle stages. Phosphorylated on Ser residue(s). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.