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 (By similarity). Interacts with sas-6 via its coiled coil domain. Localizes to centrioles. Shuttles between centrioles and the cytoplasm throughout the cell cycle. Requires zyg-1 for centriole localization (By similarity).