Protein phosphatase that negatively regulates the G1-to-S phase transition to inhibit the cell cycle and establish quiescence in cells of multiple lineages including vulval, hypodermal and intestinal (PubMed:15247923, PubMed:21723944). Promotes nuclear accumulation and activity of the cyclin-dependent kinase inhibitor cki-1 which leads to inhibition of G1 progression during vulval tissue development (PubMed:15247923). Has been shown to not be required for cytokinesis (PubMed:15247923). However, in the embryo, in a contrasting study, has been shown to act as a regulator of central spindle formation and cytokinesis, and may be required for localization of the spindle component zen-4, and its interacting partner air-2 at the spindle during late cell divisions (PubMed:12213836). Main regulator of cell cycle arrest in vulval precursor cells. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Inhibited by sodium orthovanadate. Weakly inhibited by sodium fluoride and okadaic acid. Localizes to the cytoplasm throughout interphase (PubMed:15247923). As cells enter prophase, accumulates at the centrosomes (PubMed:15247923). During metaphase and anaphase, localizes to the spindle, in particular spindle asters and the spindle mid zone (PubMed:15247923, PubMed:12213836). During late telophase, localizes to cytoplasmic aggregates (PubMed:15247923). In some studies, localizes to the midbody during late telophase (PubMed:12213836). Localizes to the cytoplasm in G1-arrested cells (PubMed:15247923). Localizes to the nucleus or nucleolus in postmitotic cells (PubMed:15247923). Some studies report no localization to centrosomes or nuclei (PubMed:12213836). Co-localizes with zen-4 at the spindle, and localization may be dependent on each other (PubMed:12213836). Localizes to the cytoplasm during interphase, but localizes to the nucleus during cell cycle arrest. Expressed in the soma during early embryogenesis, and widely expressed after hatching. Isoform C: Expressed in the soma during early embryogenesis, but after hatching, expression in larvae is restricted to V and P lineages, the postembryonic lineages that contribute to the seam cells and vulval precursor cells, respectively. RNAi-mediated knockdown results in extra cell divisions in the vulval lineage, but does not result in defects in cytokinesis (PubMed:15247923, PubMed:21723944). RNAi-mediated knockdown decreases cki-1 expression in the nucleus of vulval precursor cells (PubMed:15247923). In contrasting studies RNAi-mediated knockdown results in embryonic lethality with the production of multinucleated embryos that exhibit cytokinesis failure during telophase, no central spindle formation, and failed localization of the spindle component zen-4 and its interacting partner air-2 at the spindle in either anaphase or telophase (PubMed:12213836). Belongs to the protein-tyrosine phosphatase family. Non-receptor class CDC14 subfamily. Has been shown in one report to not be localized to centrosomes or nuclei, and based on RNAi-mediated knockdown studies, has been shown to play a role in cytokinesis (PubMed:12213836). However, has also been reported to localize to centrosomes and nuclei and to have no role in cytokinesis, based on results obtained using the cdc-14 he118 mutant and RNAi-mediated knockdown (PubMed:15247923).