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 receptor (D R) 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 D R 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 ... More
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 receptor (D R) 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 D R 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 D R-wild-type but not the mutant D R 347A that lacks a palmitoylation site. Kidney-restricted disruption of lipid rafts by β-MCD jettisoned the D R 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 D R-binding partner sorting nexin 19 (SNX19) resulted in D R partitioning solely to non-raft domains, while silencing of SNX19 impaired D R 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 D R signaling.
