TSC2 and cyst: Moreover, the mammalian target of rapamycin (mTOR) pathway was shown to be abnormally activated in cyst-lining epithelial cells in human ADPKD patients and mouse models, which may result from loss of PC1 binding with tuberin, suggesting that PC1 inhibits cell proliferation by downregulating the activity of mTOR and its interaction with tuberin [8].