lov-1 and pkd-2 encode the orthologs of human Polycystin-1 and Polycystin-2, which are mutated in autosomal dominant polycystic kidney disease; the polycystins regulate signaling involved in normal renal tubular structure and function; studies in the worm C. elegans have contributed extensively to the finding that cystic kidney diseases can be considered ciliopathies; in elegans lov-1 and pkd-2 are expressed in male ciliary neurons, are required for normal male mating behavior, do not seem to be required for ciliogenesis, and each polycystin may actually have a potential inhibitory function on the other for ciliary function; lov-1 and pkd-1 interact with a single-pass transmembrane protein, CWP-5, though the significance of this interaction for polycystic kidney disease is unknown.