Abstract 047: Sorting Nexin 19: A Novel & Key Player in Renal Dopamine D 1 R Regulation

Autor: Xiaoyan Wang, Laureano D. Asico, Andrew C Tiu, Prasad Konkalmatt, Pedro A. Jose, Jian Yang, Van Anthony M. Villar
Rok vydání: 2018
Předmět:
Zdroj: Hypertension. 72
ISSN: 1524-4563
0194-911X
DOI: 10.1161/hyp.72.suppl_1.047
Popis: The cellular localization and signal transduction of a ligand-occupied G protein-coupled receptor (GPCR) are tightly regulated to generate an appropriate response in terms of specificity, magnitude, and duration through the interplay of key proteins. We recently identified sorting nexin 19 (SNX19) as a binding partner for the renal dopamine D 1 receptor (D 1 R) and demonstrated its role in receptor lipid raft distribution and activity. We have shown that SNX19 and D 1 R co-immunoprecipitated (co-IP’d) and colocalized at the plasma membrane of human renal proximal tubule cells (hRPTCs) and at the brush border of RPTs of C57Bl/6 mice. Treatment with the D 1 R/D 5 R agonist fenoldopam promoted the colocalization to the cytoplasm of RPTCs. SNX19 silencing in hRPTCs decreased the D 1 R expression (-60±4% of basal, P1 R recruitment and endocytosis following agonist stimulation, as observed via live cell imaging. SNX19 silencing markedly decreased the fenoldopam-mediated increase in cAMP production in hRPTCs (+115±30% vs . +45±12% in mock siRNA-treated control cells, P+ ,K + -ATPase activity in polarized hRPTCs (+21±1.2% intracellular Na + vs . +2±2% in control cells, PSnx19 silencing in C57Bl/6 mice increased the systolic blood pressure (124±3 mm Hg vs . 101±2 mm Hg in control mice, P>0.05, n=5), thus demonstrating the importance of SNX19 in renal D 1 R activity and blood pressure control. SNX19 also co-IP’d with GRK4 and GODZ finger protein, an enzyme involved in GPCR palmitoylation, which is a process that promotes lipid raft partitioning. Mutation of the canonical PX domain of SNX19, which prevented its targeting to the plasma membrane, and the heterologous expression of these mutants in hRPTCs decreased the abundance of D 1 R, which became exclusively distributed in non-lipid rafts. The disruption of lipid rafts in the kidneys of mice resulted in hypertension (120±3 mm Hg vs . 101±2 mm Hg in control mice, n=4). Our results highlight the crucial role of SNX19 in the proper trafficking and functioning of renal D 1 R through its ability to promote the localization of D 1 R in lipid rafts for an effective signal transduction and appropriate cellular response.
Databáze: OpenAIRE
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