The gating of polycystin signaling complex.
Mutations in either polycystin-2 (PC2) or polycystin-1 (PC1) proteins cause severe, potentially lethal, kidney disorders (autosomal dominant polycystic kidney disease, ADPKD) and multiple extrarenal disease phenotypes. PC2, a member of the transient receptor potential channel superfamily and PC1, an orphan membrane receptor of largely unknown function, are thought to be part of a common signalling pathway. Here, I show that co-assembly of full-length PC with PC2 forms an ion channel signalling complex in which PCI regulates PC2 channel gating through a structural rearrangement of the polycystin complex (Delmas et al., 2004a). These polycystin complexes function either as a receptor-cation channel or as a G-protein-coupled receptor. Thus, PC acts as a prototypical membrane receptor that regulates G-proteins and plasmalemmal PC2, a bimodal mechanism that may account for the multifunctional roles of polycystin proteins in various cell types. Genetic alteration of polycystin proteins such as those occurring in kidney diseases may impede polycystin signalling, thereby providing a likely mechanistic explanation to the pathogenesis of ADPKD. Our proposed mechanism may also be paradigmatic for the function of polycystin orthologues and other polycystin-related proteins in a variety of nonrenal cell types, including sperm, muscle cells and sensory neurons.
Delmas
Patrick
P
Laboratoire de NeuroPhysiologie Cellulaire, CNRS-UMR 6150, Faculté de Médecine, IFR Jean Roche, Bd. Pierre Dramard, 13916 Marseille 20, France. delmas.p@jean-roche.univ-mrs.fr
D015220:Calcium Channels / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D016891:Polycystic Kidney, Autosomal Dominant / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D050396:TRPP Cation Channels
D015220:Calcium Channels; D008565:Membrane Proteins; D011506:Proteins; D050396:TRPP Cation Channels