Targeting regulators of G protein signaling (RGS proteins) to enhance agonist specificity

Regulator of G protein Signaling, or RGS, proteins serve an important regulatory role in signaling mediated by G protein-coupled receptors (GPCRs). They all share a common RGS domain that directly interacts with active, GTP-bound Gα subunits of heterotrimeric G proteins. RGS proteins stabilize the transition state for GTP hydrolysis on Gα and thus induce a conformational change in the Gα subunit that accelerates GTP hydrolysis, thereby effectively turning off signaling cascades mediated by GPCRs. This GTPase accelerating protein (GAP) activity is the canonical mechanism of action for RGS proteins, although many also possess additional functions and domains. RGS proteins are divided into four families, R4, R7, R12 and RZ based on sequence homology, domain structure as well as specificity towards Gα subunits. For reviews on RGS proteins and their potential as therapeutic targets, see e.g. [160, 377, 411, 415, 416, 512, 519, 312, 6].

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Two Chimeric Regulators of G-protein Signaling (RGS) Proteins Differentially Modulate Soybean Heterotrimeric G-protein Cycle

Journal of Biological Chemistry ◽

10.1074/jbc.m112.353219 ◽

2012 ◽

Vol 287 (21) ◽

pp. 17870-17881 ◽

Cited By ~ 20

Author(s):

Swarup Roy Choudhury ◽

Corey S. Westfall ◽

John P. Laborde ◽

Naveen C. Bisht ◽

Joseph M. Jez ◽

...

Keyword(s):

G Protein ◽

G Protein Signaling ◽

Rgs Proteins ◽

Protein Signaling ◽

Heterotrimeric G Protein

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Association with the Plasma Membrane Is Sufficient for Potentiating Catalytic Activity of Regulators of G Protein Signaling (RGS) Proteins of the R7 Subfamily

Journal of Biological Chemistry ◽

10.1074/jbc.m115.713446 ◽

2016 ◽

Vol 291 (13) ◽

pp. 7195-7204 ◽

Cited By ~ 5

Author(s):

Brian S. Muntean ◽

Kirill A. Martemyanov

Keyword(s):

Plasma Membrane ◽

Catalytic Activity ◽

G Protein ◽

G Protein Signaling ◽

Rgs Proteins ◽

Protein Signaling

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Cellular Regulation of RGS Proteins: Modulators and Integrators of G Protein Signaling

Pharmacological Reviews ◽

10.1124/pr.54.3.527 ◽

2002 ◽

Vol 54 (3) ◽

pp. 527-559 ◽

Cited By ~ 520

Author(s):

S. Hollinger

Keyword(s):

G Protein ◽

G Protein Signaling ◽

Rgs Proteins ◽

Protein Signaling ◽

Cellular Regulation

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Probing the mutational landscape of regulators of G protein signaling proteins in cancer

Science Signaling ◽

10.1126/scisignal.aax8620 ◽

2020 ◽

Vol 13 (617) ◽

pp. eaax8620 ◽

Cited By ~ 7

Author(s):

Vincent DiGiacomo ◽

Marcin Maziarz ◽

Alex Luebbers ◽

Jillian M. Norris ◽

Pandu Laksono ◽

...

Keyword(s):

G Protein ◽

G Proteins ◽

Mammalian Cells ◽

G Protein Signaling ◽

Rgs Proteins ◽

Protein Signaling ◽

Loss Of Function ◽

Gpcr Signaling ◽

Mutational Landscape ◽

Binding Interface

The advent of deep-sequencing techniques has revealed that mutations in G protein–coupled receptor (GPCR) signaling pathways in cancer are more prominent than was previously appreciated. An emergent theme is that cancer-associated mutations tend to cause enhanced GPCR pathway activation to favor oncogenicity. Regulators of G protein signaling (RGS) proteins are critical modulators of GPCR signaling that dampen the activity of heterotrimeric G proteins through their GTPase-accelerating protein (GAP) activity, which is conferred by a conserved domain dubbed the “RGS-box.” Here, we developed an experimental pipeline to systematically assess the mutational landscape of RGS GAPs in cancer. A pan-cancer bioinformatics analysis of the 20 RGS domains with GAP activity revealed hundreds of low-frequency mutations spread throughout the conserved RGS domain structure with a slight enrichment at positions that interface with G proteins. We empirically tested multiple mutations representing all RGS GAP subfamilies and sampling both G protein interface and noninterface positions with a scalable, yeast-based assay. Last, a subset of mutants was validated using G protein activity biosensors in mammalian cells. Our findings reveal that a sizable fraction of RGS protein mutations leads to a loss of function through various mechanisms, including disruption of the G protein–binding interface, loss of protein stability, or allosteric effects on G protein coupling. Moreover, our results also validate a scalable pipeline for the rapid characterization of cancer-associated mutations in RGS proteins.

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