Succinate receptor GPR91, a Gα_i coupled receptor that increases intracellular calcium concentrations through PLCβ

Abstract

Edited by Lukas HuberKeywords: GPCR GPR91 Succinate PLCb PTX a b s t r a c t Succinate has been reported as the endogenous ligand for GPR91. In this study, succinate was confirmed to activate GPR91 resulting in both 3 0 -5 0 -cyclic adenosine monophosphate (cAMP) inhibition and inositol phosphate formation in a pertussis toxin (PTX)-sensitive manner. GPR91 agonist-mediated effects detected using dynamic mass redistribution (DMR) were inhibited with PTX, edelfosine and U73122 demonstrating the importance of not only the Ga i pathway but also PLCb. These results show that GPR91 when expressed in HEK293s cells couples exclusively through the Ga i pathway and acts through Ga i not only to inhibit cAMP production but also to increase intracellular Ca 2+ in an inositol phosphate dependent mechanism via PLCb activation.

Forskolin-free cAMP assay for Gi-coupled receptors

“…The view of SUCNR1 being coupled to G q has been later challenged. Sundstrom et al proposed that the [Ca 2+ ] i mobilization was a consequence of PLC-b activation by the dimer Gbg [41]. Our observation that SA elicits a concentration-dependent PTXsensitive [Ca 2+ ] i mobilization is consistent with SUCNR1 being not coupled to G q , at least when heterologously expressed in HEK293 cells.…”

Regulation of Vascular and Renal Function by Metabolite Receptors

“…GPR91 and GPR99 are cell surface receptors and can be rapidly internalized like other GPCRs (12). A variety of intracellular signaling mechanisms—including inositol trisphosphate (IP 3 ) and Ca 2 + (12, 15), cAMP (13, 23), and mitogen-activated protein (MAP) kinases p38 and ERK1/2 (15–17, 24)—have been linked to GPR91 and GPR99 activation via either the pertussis-toxin-sensitive G i /G o pathway or the pertussis-toxin-insensitive G q pathway (Figure 2). The detailed tissue distribution, signaling pathways, and (patho)physiological roles of GPR91 and GPR99 were recently reviewed (25, 26).…”

Insight into SUCNR1 (GPR91) structure and function

“…Several authors repeatedly confirmed G i activation by demonstrating a decrease of cAMP levels upon succinate binding to SUCNR1 (Fig. 3), in both heterologous and native systems (Gilissen et al, 2015;Gnana-Prakasam et al, 2011 ;Hakak et al, 2009;Hogberg et al, 2011 ;Sundström et al, 2013). However, the view of SUCNR1 being coupled to G q has been challenged and it was proposed by several authors that the observed [Ca 2+ ] i mobilization was a consequence of PLC-β activation by the βγ dimer (Fig.…”

“…However, the view of SUCNR1 being coupled to G q has been challenged and it was proposed by several authors that the observed [Ca 2+ ] i mobilization was a consequence of PLC-β activation by the βγ dimer (Fig. 3) (Gilissen et al, 2015;Sundström et al, 2013). The discrepancy between results may reflect distinct G protein partners among different cell types or artifacts induced by overexpression of the receptor.…”