Polycystin-related proteins are a family of proteins, some of which have been shown to be able to form cation-conducting transmembrane channels. In mammals, the polycystin complex is a heteromeric complex of the polycystin proteins, PKD1 (PC-1) and PKD2 (PC-2/TRPP1) that can act as a cation channel. Some members are also members of the Transient Receptor Potential (TRP) channel superfamily. (Adapted from FBrf0253843 and the Transporter Classification Database.)