INPP5E and polycystic kidney disease: When Inpp5e is conditionally inactivated in the mouse kidney epithelium, its loss causes severe polycystic kidney disease (Hakim et al., 2016) due to the loss of INPP5E 5-phosphatase-mediated hydrolysis of PtdIns(3,4,5)P3, which results in increased pAkt and the activation of the mTOR growth pathway.