Binds, sorts and targets the polycystin complex (lov-1 and pkd-2) for lysosomal degradation, acting on early endosomes located at the ciliary base. Functions in the germline together with the ephrin receptor (vab-1) signaling pathway to negatively regulate MAPK activation. May have a role as a positive regulator of meiotic maturation in oocytes, acting independently of vab-1. Isoform a, but not isoform b, interacts (via C-terminus) with lov-1 (via C-terminus). Located to early endosomes at the ciliary base but not cilium proper of male-specific sensory neurons. Widely expressed, including the pharyngeal intestinal valve, several head neurons, and phasmids in both males and hermaphrodites throughout development. In males, also expressed in the gonad and sensory neurons in the tail. Expressed in the male-specific ciliate CEM, ray B-type and hook HOB sensory neurons. Belongs to the STAM family.