Serine/threonine-protein phosphatase essential for chromosomal dynamics during meiosis and mitosis. During meiosis, promotes chromosomal cohesion and germline immortality via a small RNA-mediated genome silencing pathway (PubMed:30921322). Antagonizes the function of air-2 kinase during meiosis I and mitosis to promote chromatid cohesion and spindle attachment (PubMed:18923084). Dephosphorylates histone H3 at 'Ser-10' (Probable). Dephosphorylates histone H3 at 'Thr-3' (Probable). Also involved in the activation of chloride channel clh-3 during cell swelling and meiotic maturation. Promotes small RNA-mediated genome silencing over multiple generations (PubMed:30921322). Essential for embryogenesis. 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. Inhibited by okadaic acid. Interacts with lab-1; the interaction is direct. Localizes to nuclei in the mid-pachytene to diplotene phase of meiosis. Expressed in gonads, nervous system, intestine and muscles. Expressed at early embryonic stages. Belongs to the PPP phosphatase family. PP-1 subfamily.