scholarly journals Palmitoylation regulates plasma membrane–nuclear shuttling of R7BP, a novel membrane anchor for the RGS7 family

2005 ◽  
Vol 169 (4) ◽  
pp. 623-633 ◽  
Author(s):  
Ryan M. Drenan ◽  
Craig A. Doupnik ◽  
Maureen P. Boyle ◽  
Louis J. Muglia ◽  
James E. Huettner ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Potassium Channel ◽  
G Protein ◽  
Rgs Proteins ◽  
Membrane Anchor ◽  
Channel Activation ◽  
Gpcr Signaling ◽  
Inward Rectifying Potassium Channel ◽  
Nuclear Shuttling ◽  
G Protein Coupled

The RGS7 (R7) family of RGS proteins bound to the divergent Gβ subunit Gβ5 is a crucial regulator of G protein–coupled receptor (GPCR) signaling in the visual and nervous systems. Here, we identify R7BP, a novel neuronally expressed protein that binds R7–Gβ5 complexes and shuttles them between the plasma membrane and nucleus. Regional expression of R7BP, Gβ5, and R7 isoforms in brain is highly coincident. R7BP is palmitoylated near its COOH terminus, which targets the protein to the plasma membrane. Depalmitoylation of R7BP translocates R7BP–R7–Gβ5 complexes from the plasma membrane to the nucleus. Compared with nonpalmitoylated R7BP, palmitoylated R7BP greatly augments the ability of RGS7 to attenuate GPCR-mediated G protein–regulated inward rectifying potassium channel activation. Thus, by controlling plasma membrane nuclear–shuttling of R7BP–R7–Gβ5 complexes, reversible palmitoylation of R7BP provides a novel mechanism that regulates GPCR signaling and potentially transduces signals directly from the plasma membrane to the nucleus.

scholarly journals GPR158/179 regulate G protein signaling by controlling localization and activity of the RGS7 complexes

2012 ◽  
Vol 197 (6) ◽  
pp. 711-719 ◽  
Author(s):  
Cesare Orlandi ◽  
Ekaterina Posokhova ◽  
Ikuo Masuho ◽  
Thomas A. Ray ◽  
Nazarul Hasan ◽  
...  
Keyword(s):  
G Protein ◽  
Night Vision ◽  
G Protein Signaling ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Gpcr Signaling ◽  
Signaling Specificity ◽  
Orphan Gpcrs ◽  
G Protein Coupled

The extent and temporal characteristics of G protein–coupled receptor (GPCR) signaling are shaped by the regulator of G protein signaling (RGS) proteins, which promote G protein deactivation. With hundreds of GPCRs and dozens of RGS proteins, compartmentalization plays a key role in establishing signaling specificity. However, the molecular details and mechanisms of this process are poorly understood. In this paper, we report that the R7 group of RGS regulators is controlled by interaction with two previously uncharacterized orphan GPCRs: GPR158 and GPR179. We show that GPR158/179 recruited RGS complexes to the plasma membrane and augmented their ability to regulate GPCR signaling. The loss of GPR179 in a mouse model of night blindness prevented targeting of RGS to the postsynaptic compartment of bipolar neurons in the retina, illuminating the role of GPR179 in night vision. We propose that the interaction of RGS proteins with orphan GPCRs promotes signaling selectivity in G protein pathways.

scholarly journals A Physiologically Required G Protein-coupled Receptor (GPCR)-Regulator of G Protein Signaling (RGS) Interaction That Compartmentalizes RGS Activity

2013 ◽  
Vol 288 (38) ◽  
pp. 27327-27342 ◽  
Author(s):  
Wayne Croft ◽  
Claire Hill ◽  
Eilish McCann ◽  
Michael Bond ◽  
Manuel Esparza-Franco ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Signaling ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Gpcr Signaling ◽  
Additional Layer ◽  
Physiological Relevance ◽  
Gtpase Cycle ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) can interact with regulator of G protein signaling (RGS) proteins. However, the effects of such interactions on signal transduction and their physiological relevance have been largely undetermined. Ligand-bound GPCRs initiate by promoting exchange of GDP for GTP on the Gα subunit of heterotrimeric G proteins. Signaling is terminated by hydrolysis of GTP to GDP through intrinsic GTPase activity of the Gα subunit, a reaction catalyzed by RGS proteins. Using yeast as a tool to study GPCR signaling in isolation, we define an interaction between the cognate GPCR (Mam2) and RGS (Rgs1), mapping the interaction domains. This reaction tethers Rgs1 at the plasma membrane and is essential for physiological signaling response. In vivo quantitative data inform the development of a kinetic model of the GTPase cycle, which extends previous attempts by including GPCR-RGS interactions. In vivo and in silico data confirm that GPCR-RGS interactions can impose an additional layer of regulation through mediating RGS subcellular localization to compartmentalize RGS activity within a cell, thus highlighting their importance as potential targets to modulate GPCR signaling pathways.

scholarly journals WIN55,212-2, a Dual Modulator of Cannabinoid Receptors and G Protein-Coupled Inward Rectifier Potassium Channels

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 484
Author(s):  
Dongchen An ◽  
Steve Peigneur ◽  
Jan Tytgat
Keyword(s):  
Potassium Channels ◽  
Potassium Channel ◽  
G Protein ◽  
Cannabinoid Receptors ◽  
Inward Rectifier ◽  
Xenopus Laevis Oocyte ◽  
Inward Rectifier Potassium Channels ◽  
Wide Range ◽  
Cb2 Receptors ◽  
G Protein Coupled

The coupling of cannabinoid receptors, CB1 and CB2, to G protein-coupled inward rectifier potassium channels, GIRK1 and GIRK2, modulates neuronal excitability in the human brain. The present study established and validated the functional expression in a Xenopus laevis oocyte expression system of CB1 and CB2 receptors, interacting with heteromeric GIRK1/2 channels and a regulator of G protein signaling, RGS4. This ex vivo system enables the discovery of a wide range of ligands interacting orthosterically or allosterically with CB1 and/or CB2 receptors. WIN55,212-2, a non-selective agonist of CB1 and CB2, was used to explore the CB1- or CB2-GIRK1/2-RGS4 signaling cascade. We show that WIN55,212-2 activates CB1 and CB2 at low concentrations whereas at higher concentrations it exerts a direct block of GIRK1/2. This illustrates a dual modulatory function, a feature not described before, which helps to explain the adverse effects induced by WIN55,212-2 in vivo. When comparing the effects with other typical cannabinoids such as Δ9-THC, CBD, CP55,940, and rimonabant, only WIN55,212-2 can significantly block GIRK1/2. Interestingly, the inward rectifier potassium channel, IRK1, a non-G protein-coupled potassium channel important for setting the resting membrane voltage and highly similar to GIRK1 and GIRK2, is not sensitive to WIN55,212-2, Δ9-THC, CBD, CP55,940, or rimonabant. From this, it is concluded that WIN55,212-2 selectively blocks GIRK1/2.

scholarly journals Rgs4 is a regulator of mTOR activity required for motoneuron axon outgrowth and neuronal development in zebrafish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aya Mikdache ◽  
Marie-José Boueid ◽  
Lorijn van der Spek ◽  
Emilie Lesport ◽  
Brigitte Delespierre ◽  
...  
Keyword(s):  
Nervous System ◽  
G Protein ◽  
Neural Development ◽  
Neuronal Development ◽  
Axon Outgrowth ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Loss Of Function ◽  
G Protein Coupled

AbstractThe Regulator of G protein signaling 4 (Rgs4) is a member of the RGS proteins superfamily that modulates the activity of G-protein coupled receptors. It is mainly expressed in the nervous system and is linked to several neuronal signaling pathways; however, its role in neural development in vivo remains inconclusive. Here, we generated and characterized a rgs4 loss of function model (MZrgs4) in zebrafish. MZrgs4 embryos showed motility defects and presented reduced head and eye sizes, reflecting defective motoneurons axon outgrowth and a significant decrease in the number of neurons in the central and peripheral nervous system. Forcing the expression of Rgs4 specifically within motoneurons rescued their early defective outgrowth in MZrgs4 embryos, indicating an autonomous role for Rgs4 in motoneurons. We also analyzed the role of Akt, Erk and mechanistic target of rapamycin (mTOR) signaling cascades and showed a requirement for these pathways in motoneurons axon outgrowth and neuronal development. Drawing on pharmacological and rescue experiments in MZrgs4, we provide evidence that Rgs4 facilitates signaling mediated by Akt, Erk and mTOR in order to drive axon outgrowth in motoneurons and regulate neuronal numbers.

scholarly journals Imaging of persistent cAMP signaling by internalized G protein-coupled receptors

2010 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Davide Calebiro ◽  
Viacheslav O Nikolaev ◽  
Martin J Lohse
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
Current Model ◽  
Living Cells ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Optical Methods ◽  
Camp Signaling ◽  
Gpcr Signaling ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are the largest family of plasma membrane receptors. They mediate the effects of several endogenous cues and serve as important pharmacological targets. Although many biochemical events involved in GPCR signaling have been characterized in great detail, little is known about their spatiotemporal dynamics in living cells. The recent advent of optical methods based on fluorescent resonance energy transfer allows, for the first time, to directly monitor GPCR signaling in living cells. Utilizing these methods, it has been recently possible to show that the receptors for two protein/peptide hormones, the TSH and the parathyroid hormone, continue signaling to cAMP after their internalization into endosomes. This type of intracellular signaling is persistent and apparently triggers specific cellular outcomes. Here, we review these recent data and explain the optical methods used for such studies. Based on these findings, we propose a revision of the current model of the GPCR–cAMP signaling pathway to accommodate receptor signaling at endosomes.

scholarly journals Comment on "A G Protein Coupled Receptor Is a Plasma Membrane Receptor for the Plant Hormone Abscisic Acid"

Science ◽  
2007 ◽  
Vol 318 (5852) ◽  
pp. 914c-914c ◽  
Author(s):  
C. A. Johnston ◽  
B. R. Temple ◽  
J.-G. Chen ◽  
Y. Gao ◽  
E. N. Moriyama ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Abscisic Acid ◽  
G Protein ◽  
Plant Hormone ◽  
Membrane Receptor ◽  
G Protein Coupled Receptor ◽  
Plasma Membrane Receptor ◽  
G Protein Coupled
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