Protein kinase that seems to play a role in the regulation of cell morphogenesis and proliferation. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Associates with PAG1/TAO3 and interacts with MOB2. Present with 450 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. STE Ser/Thr protein kinase family. COT1 subfamily.