Required for centrosome duplication. Essential for daughter-centriole formation. Requires both maternal and partenal expression, suggesting that it regulates centriole duplication during both spermatogenesis and early embryogenesis. Interacts with sas-6 via its coiled coil domain. Interacts (via C terminus) with let-92 (part of the PP2A complex). Localizes to centrioles. Shuttles between centrioles and the cytoplasm throughout the cell cycle. Requires zyg-1 and dephosphorylation by the PP2A complex for centriole localization. Present in germ cells during early oogenesis, but not during late oogenesis.