PKD2 and autosomal dominant polycystic kidney disease: The complexes of PKD1 and TRPP2 exhibit a 1:3 structural ratio.131 TRPP2 and PKD1 bind directly through their C-termini to form a complex containing three TRPP2 and one PKD1.132 This association involves a coiled-coil structure at the C-terminus of both proteins.125 R807X, E837X, and R872X of TRPP2 and R4227X and Y4236X of PKD1 can lead to deletion of the coiled-coil structural domain, which results in the mutation of ADPKD.133,134