TY - JOUR
T1 - Proteolytic degradation of regulator of G protein signaling 2 facilitates temporal regulation of Gq/11 signaling and vascular contraction
AU - Kanai, Stanley M.
AU - Edwards, Alethia J.
AU - Rurik, Joel G.
AU - Osei-Owusu, Patrick
AU - Blumer, Kendall J.
N1 - Publisher Copyright:
© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2017/11/24
Y1 - 2017/11/24
N2 - Regulator of G protein signaling 2 (RGS2) controls signaling by receptors coupled to the Gq/11 class heterotrimeric G proteins. RGS2 deficiency causes several phenotypes in mice and occurs in several diseases, including hypertension in which a proteolytically unstable RGS2 mutant has been reported. However, the mechanisms and functions of RGS2 proteolysis remain poorly understood. Here we addressed these questions by identifying degradation signals in RGS2, and studying dynamic regulation of Gq/11-evoked Ca2 signaling and vascular contraction. We identified a novel bipartite degradation signal in the N-terminal domain of RGS2. Mutations disrupting this signal blunted proteolytic degradation downstream of E3 ubiquitin ligase binding to RGS2. Analysis of RGS2 mutants proteolyzed at various rates and the effects of proteasome inhibition indicated that proteolytic degradation controls agonist efficacy by setting RGS2 protein expression levels, and affecting the rate at which cells regain agonist responsiveness as synthesis of RGS2 stops. Analyzing contraction of mesenteric resistance arteries supported the biological relevance of this mechanism. Because RGS2 mRNA expression often is strikingly and transiently upregulated and then down-regulated upon cell stimulation, our findings indicate that proteolytic degradation tightly couples RGS2 transcription, protein levels, and function. Together these mechanisms provide tight temporal control of Gq/11-coupled receptor signaling in the cardiovascular, immune, and nervous systems.
AB - Regulator of G protein signaling 2 (RGS2) controls signaling by receptors coupled to the Gq/11 class heterotrimeric G proteins. RGS2 deficiency causes several phenotypes in mice and occurs in several diseases, including hypertension in which a proteolytically unstable RGS2 mutant has been reported. However, the mechanisms and functions of RGS2 proteolysis remain poorly understood. Here we addressed these questions by identifying degradation signals in RGS2, and studying dynamic regulation of Gq/11-evoked Ca2 signaling and vascular contraction. We identified a novel bipartite degradation signal in the N-terminal domain of RGS2. Mutations disrupting this signal blunted proteolytic degradation downstream of E3 ubiquitin ligase binding to RGS2. Analysis of RGS2 mutants proteolyzed at various rates and the effects of proteasome inhibition indicated that proteolytic degradation controls agonist efficacy by setting RGS2 protein expression levels, and affecting the rate at which cells regain agonist responsiveness as synthesis of RGS2 stops. Analyzing contraction of mesenteric resistance arteries supported the biological relevance of this mechanism. Because RGS2 mRNA expression often is strikingly and transiently upregulated and then down-regulated upon cell stimulation, our findings indicate that proteolytic degradation tightly couples RGS2 transcription, protein levels, and function. Together these mechanisms provide tight temporal control of Gq/11-coupled receptor signaling in the cardiovascular, immune, and nervous systems.
UR - http://www.scopus.com/inward/record.url?scp=85035127144&partnerID=8YFLogxK
U2 - 10.1074/jbc.M117.797134
DO - 10.1074/jbc.M117.797134
M3 - Article
C2 - 28974581
AN - SCOPUS:85035127144
VL - 292
SP - 19266
EP - 19278
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 47
ER -