Protein phosphatase which plays an essential role in meiosis and in early embryonic mitosis (PubMed:11896188, PubMed:25340746). During spermatocyte meiosis and the first embryonic mitosis, regulates centrosome maturation, and thus spindle formation, by recruiting some of the components of the pericentriolar material (PCM) (PubMed:11896188). During oocyte meiosis I, regulates meiotic chromosome dynamics including synapsis-independent chromosome pairing, restriction of synapsis to homologous chromosomes, programmed DNA double-strand break initiation and crossover formation resulting in chiasma formation (PubMed:11896188, PubMed:25340746). During oocyte meiosis II and probably together with regulatory subunit ppfr-1, may regulate microtubule severing by dephosphorylating and activating mei-1, a component of the katanin microtubule severing complex (PubMed:19087961). H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Binds 2 manganese ions per subunit. Serine/threonine-protein phosphatase 4 (PP4) occurs in different assemblies of the catalytic and one or more regulatory subunits (By similarity). The regulatory subunits are likely to be ppfr-1, ppfr-2, ppfr-4 and smk-1 (PubMed:19087961). Interacts with mei-1 (PubMed:19087961). Localizes at centrosomes from prophase to telophase but not during interphase. Also localizes to the cytoplasm throughout the cell cycle. Expressed in embryos (at protein level). Methylation at the C-terminal Leu-333 is critical for interactions with regulatory subunits. Severe embryonic lethality associated with a high incidence of male progeny (PubMed:25340746). RNAi-mediated knockdown causes 20 percent embryonic lethality and 18 percent larval lethality (PubMed:11896188). Abnormal meiosis and mitosis leading to defects in gametogenesis and embryogenesis (PubMed:11896188, PubMed:25340746). In spermatocytes, defects in the organization of astral microtubules (PubMed:11896188). In oocyte meiosis I, defects in autosomal chromosome pairing resulting from abnormal synapsis (PubMed:25340746). In embryos, RNAi-mediated knockdown causes abnormal mitosis due to defects in astral microtubules organization (PubMed:11896188). In a gain of function mei-1 (ct46) or in mel-26 (ct61sb4) mutant background, RNAi-mediated knockdown partially rescues embryonic lethality without affecting mei-1 expression levels and localization (PubMed:19087961). Belongs to the PPP phosphatase family. PP-4 (PP-X) subfamily. Truncated N-terminus.