Polycystin 2 regulates mitochondrial Ca ²⁺ signaling, bioenergetics, and dynamics through mitofusin 2

transfer and diminished cell proliferation in kidney cysts. Consistent with these results, cyst-lining epithelial cells from human ADPKD kidneys had a twofold increase in mitochondria and MFN2 expression. Our data suggest that PC2 normally serves to limit key mitochondrial proteins at the ER-mitochondrial interface and acts as a checkpoint for mitochondrial biogenesis and bioenergetics. Loss of this regulation may contribute to the increased oxidative metabolism and aberrant cell proliferation typical of kidney cysts in ADPKD.