Required for cytoplasmic partitioning and asymmetric cell division in early embryogenesis. Phosphorylates and restricts the asymmetry effector mex-5 (and possibly also mex-6) to the anterior cytoplasm of the zygote. Regulates mes-1 expression during early embryogenesis. Critical role in postembryonic vulval morphogenesis. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Colocalizes with germ granules (P granules). Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. SNF1 subfamily.