Serine/threonine-protein kinase which may play a role in lin-12-mediated cell-fate decisions. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] No obvious phenotype. RNAi-mediated knockdown suppresses the egg laying defect of lin-12 n302 mutant. A similar phenotype occurs in a lin-12 and sel-5 double mutant. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.