A Highly Conserved Glycine within Linker I and the Extreme C Terminus of G Protein α Subunits Interact Cooperatively in Switching G Protein-Coupled Receptor-to-Effector Specificity

2004 ◽  
Vol 313 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Evi Kostenis ◽  
Lene Martini ◽  
James Ellis ◽  
Maria Waldhoer ◽  
Arne Heydorn ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptor ◽  
C Terminus ◽  
G Protein Coupled ◽  
Α Subunits ◽  
G Protein Α Subunits

scholarly journals Regulation of the Epithelial Na+ Channel by the RH Domain of G Protein-coupled Receptor Kinase, GRK2, and Gαq/11

2011 ◽  
Vol 286 (22) ◽  
pp. 19259-19269 ◽  
Author(s):  
Il-Ha Lee ◽  
Sung-Hee Song ◽  
Craig R. Campbell ◽  
Sharad Kumar ◽  
David I. Cook ◽  
...  
Keyword(s):  
G Protein ◽  
Kinase Activity ◽  
Receptor Activation ◽  
Na Channel ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Receptor Kinase ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled ◽  
Α Subunits

The G protein-coupled receptor kinase (GRK2) belongs to a family of protein kinases that phosphorylates agonist-activated G protein-coupled receptors, leading to G protein-receptor uncoupling and termination of G protein signaling. GRK2 also contains a regulator of G protein signaling homology (RH) domain, which selectively interacts with α-subunits of the Gq/11 family that are released during G protein-coupled receptor activation. We have previously reported that kinase activity of GRK2 up-regulates activity of the epithelial sodium channel (ENaC) in a Na+ absorptive epithelium by blocking Nedd4-2-dependent inhibition of ENaC. In the present study, we report that GRK2 also regulates ENaC by a mechanism that does not depend on its kinase activity. We show that a wild-type GRK2 (wtGRK2) and a kinase-dead GRK2 mutant (K220RGRK2), but not a GRK2 mutant that lacks the C-terminal RH domain (ΔRH-GRK2) or a GRK2 mutant that cannot interact with Gαq/11/14 (D110AGRK2), increase activity of ENaC. GRK2 up-regulates the basal activity of the channel as a consequence of its RH domain binding the α-subunits of Gq/11. We further found that expression of constitutively active Gαq/11 mutants significantly inhibits activity of ENaC. Conversely, co-expression of siRNA against Gαq/11 increases ENaC activity. The effect of Gαq on ENaC activity is not due to change in ENaC membrane expression and is independent of Nedd4-2. These findings reveal a novel mechanism by which GRK2 and Gq/11 α-subunits regulate the activity ENaC.

scholarly journals Closely Related G-protein-coupled Receptors Use Multiple and Distinct Domains on G-protein α-Subunits for Selective Coupling

2003 ◽  
Vol 278 (50) ◽  
pp. 50530-50536 ◽  
Author(s):  
Janna E. Slessareva ◽  
Hongzheng Ma ◽  
Karyn M. Depree ◽  
Lori A. Flood ◽  
Hyunsu Bae ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled ◽  
Α Subunits ◽  
G Protein Α Subunits

scholarly journals Plasma Membrane and Nuclear Localization of G Protein–coupled Receptor Kinase 6A

2007 ◽  
Vol 18 (8) ◽  
pp. 2960-2969 ◽  
Author(s):  
Xiaoshan Jiang ◽  
Jeffrey L. Benovic ◽  
Philip B. Wedegaertner
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
G Protein ◽  
Nuclear Localization ◽  
Nuclear Export ◽  
Amphipathic Helix ◽  
G Protein Coupled Receptor ◽  
C Terminus ◽  
Acidic Residues ◽  
G Protein Coupled

G protein–coupled receptor (GPCR) kinases (GRKs) specifically phosphorylate agonist-occupied GPCRs at the inner surface of the plasma membrane (PM), leading to receptor desensitization. Here we show that the C-terminal 30 amino acids of GRK6A contain multiple elements that either promote or inhibit PM localization. Disruption of palmitoylation by individual mutation of cysteine 561, 562, or 565 or treatment of cells with 2-bromopalmitate shifts GRK6A from the PM to both the cytoplasm and nucleus. Likewise, disruption of the hydrophobic nature of a predicted amphipathic helix by mutation of two leucines to alanines at positions 551 and 552 causes a loss of PM localization. Moreover, acidic amino acids in the C-terminus appear to negatively regulate PM localization; mutational replacement of several acidic residues with neutral or basic residues rescues PM localization of a palmitoylation-defective GRK6A. Last, we characterize the novel nuclear localization, showing that nuclear export of nonpalmitoylated GRK6A is sensitive to leptomycin B and that GRK6A contains a potential nuclear localization signal. Our results suggest that the C-terminus of GRK6A contains a novel electrostatic palmitoyl switch in which acidic residues weaken the membrane-binding strength of the amphipathic helix, thus allowing changes in palmitoylation to regulate PM versus cytoplasmic/nuclear localization.

scholarly journals A yeast screening method to decipher the interaction between the adenosine A2B receptor and the C-terminus of different G protein α-subunits

2014 ◽  
Vol 10 (3) ◽  
pp. 441-453 ◽  
Author(s):  
Rongfang Liu ◽  
Nick J. A. Groenewoud ◽  
Miriam C. Peeters ◽  
Eelke B. Lenselink ◽  
Ad P. IJzerman
Keyword(s):  
G Protein ◽  
Screening Method ◽  
Adenosine A2b Receptor ◽  
C Terminus ◽  
A2b Receptor ◽  
Α Subunits ◽  
G Protein Α Subunits ◽  
Adenosine A2b
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