Required for cytoplasmic partitioning and asymmetric cell division in early embryogenesis (PubMed:7758115). Phosphorylates and restricts the asymmetry effector mex-5 (and possibly also mex-6) to the anterior cytoplasm of the zygote (PubMed:18842813). Regulates mes-1 expression during early embryogenesis (PubMed:11003841). Critical role in postembryonic vulval morphogenesis (PubMed:12490197). Involved in the establishment of neuronal polarity (PubMed:20023164). 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). Asymmetrically localized to the posterior of the zygote before mitotic division, then differentially distributed to the germline precursor cells (at protein level). Maternally expressed. Phosphorylated at Thr-325 probably by par-4. Maternal effect lethality. Blastomeres cleave synchronously until the fourth or fifth round, when synchrony breaks down. Cells also fail to segregate P granules. Terminal stage embryos fail to produce intestinal cells. Disruption post-hatching results in a protruding vulva, the two mirror-symmetric halves of the vulva fail to join into a single, coherent organ. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. SNF1 subfamily.