This protein is a negative regulator of both sexual conjugation and meiosis. It phosphorylates mei2. It blocks the onset of meiosis until conjugation takes place. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.