TSC1 and cyst: While PC-1 primarily resides on the cilia of principal cells, it is also present on other cell membranes, including intercalated cells, and is highly expressed on extracellular vesicles [88].Genetic studies have shown that mTORC1-mediated PC-1 suppression leads to cyst formation in Tsc1 mutants, potentially clarifying the severe renal manifestations in the PKD1/TSC2 contiguous gene syndrome [89].