Part of a signaling pathway. Required for initiation of medial ring constriction and septation. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with mob1 and cdc11. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.