Lipid rafts are required for effective renal D1 dopamine receptor function

Abstract

Effective receptor signaling is anchored on the preferential localization of the receptor in lipid rafts, which are plasma membrane platforms replete with cholesterol and sphingolipids. We hypothesized that the dopamine D-1 receptor (D1R) contains structural features that allow it to reside in lipid rafts for its activity. Mutation of C347 palmitoylation site and Y218 of a newly identified Cholesterol Recognition Amino Acid Consensus motif resulted in the exclusion of D1R from lipid rafts, blunted cAMP response, impaired sodium transport, and increased oxidative stress in renal proximal tubule cells (RPTCs). Kidney-restricted silencing of Drd1 in C57BL/6J mice increased blood pressure (BP) that was normalized by renal tubule-restricted rescue with D1R-wild-type but not the mutant D1R 347A that lacks a palmitoylation site. Kidney-restricted disruption of lipid rafts by beta-MCD jettisoned the D1R from the brush border, decreased sodium excretion, and increased oxidative stress and BP in C57BL/6J mice. Deletion of the PX domain of the novel D1R-binding partner sorting nexin 19 (SNX19) resulted in D1R partitioning solely to non-raft domains, while silencing of SNX19 impaired D1R function in RPTCs. Kidney-restricted silencing of Snx19 resulted in hypertension in C57BL/6J mice. Our results highlight the essential role of lipid rafts for effective D1R signaling.