The polycystins are modulated by cellular oxygen-sensing pathways and regulate mitochondrial function

Abstract

The polycystin proteins are encoded by the genes mutated in autosomal dominant polycystic kidney disease. A new role for these proteins in oxygen sensing and cell metabolism is proposed. Oxygen regulates the trafficking and channel activity of the polycystin complex, which modulates mitochondrial function by altering mitochondrial calcium uptake.

Abstract

Autosomal dominant polycystic kidney disease is caused by mutations in the genes encoding polycystin-1 (PC1) and polycystin-2 (PC2), which form an ion channel complex that may mediate ciliary sensory processes and regulate endoplasmic reticulum (ER) Ca ²⁺ release. Loss of PC1 expression profoundly alters cellular energy metabolism. The mechanisms that control the trafficking of PC1 and PC2, as well as their broader physiological roles, are poorly understood. We found that O ₂ levels regulate the subcellular localization and channel activity of the polycystin complex through its interaction with the O ₂-sensing prolyl hydroxylase domain containing protein EGLN3 (or PHD3), which hydroxylates PC1. Moreover, cells lacking PC1 expression use less O ₂ and show less mitochondrial Ca ²⁺ uptake in response to bradykinin-induced ER Ca ²⁺ release, indicating that PC1 can modulate mitochondrial function. These data suggest a novel role for the polycystins in sensing and responding to cellular O ₂ levels.