scholarly journals The G protein–coupled receptor GPR31 promotes membrane association of KRAS

2017 ◽  
Vol 216 (8) ◽  
pp. 2329-2338 ◽  
Author(s):  
Nicole Fehrenbacher ◽  
Israel Tojal da Silva ◽  
Craig Ramirez ◽  
Yong Zhou ◽  
Kwang-Jin Cho ◽  
...  

The product of the KRAS oncogene, KRAS4B, promotes tumor growth when associated with the plasma membrane (PM). PM association is mediated, in part, by farnesylation of KRAS4B, but trafficking of nascent KRAS4B to the PM is incompletely understood. We performed a genome-wide screen to identify genes required for KRAS4B membrane association and identified a G protein–coupled receptor, GPR31. GPR31 associated with KRAS4B on cellular membranes in a farnesylation-dependent fashion, and retention of GPR31 on the endoplasmic reticulum inhibited delivery of KRAS4B to the PM. Silencing of GPR31 expression partially mislocalized KRAS4B, slowed the growth of KRAS-dependent tumor cells, and blocked KRAS-stimulated macropinocytosis. Our data suggest that GPR31 acts as a secretory pathway chaperone for KRAS4B.

2010 ◽  
Vol 21 (24) ◽  
pp. 4338-4348 ◽  
Author(s):  
Hannah C. Chapin ◽  
Vanathy Rajendran ◽  
Michael J. Caplan

Polycystin (PC)1 and PC2 are membrane proteins implicated in autosomal dominant polycystic kidney disease. A physiologically relevant cleavage at PC1's G protein-coupled receptor proteolytic site (GPS) occurs early in the secretory pathway. Our results suggest that PC2 increases both PC1 GPS cleavage and PC1's appearance at the plasma membrane. Mutations that prevent PC1's GPS cleavage prevent its plasma membrane localization. PC2 is a member of the trp family of cation channels and is an important PC1 binding partner. The effect of PC2 on PC1 localization is independent of PC2 channel activity, as tested using channel-inhibiting PC2 mutations. PC1 and PC2 can interact through their C-terminal tails, but removing the C-terminal tail of either protein has no effect on PC1 surface localization in human embryonic kidney 293 cells. Experiments in polarized LLC-PK cells show that apical and ciliary PC1 localization requires PC2 and that this delivery is sensitive to PC2 truncation. In sum, our work shows that PC2 expression is required for the movement of PC1 to the plasma and ciliary membranes. In fibroblast cells this localization effect is independent of PC2's channel activity or PC1 binding ability but involves a stimulation of PC1's GPS cleavage before the PC1 protein's surface delivery.


Science ◽  
2007 ◽  
Vol 318 (5852) ◽  
pp. 914c-914c ◽  
Author(s):  
C. A. Johnston ◽  
B. R. Temple ◽  
J.-G. Chen ◽  
Y. Gao ◽  
E. N. Moriyama ◽  
...  

2010 ◽  
Vol 184 (11) ◽  
pp. 6188-6198 ◽  
Author(s):  
Susanna Valanne ◽  
Henna Myllymäki ◽  
Jenni Kallio ◽  
Martin Rudolf Schmid ◽  
Anni Kleino ◽  
...  

2012 ◽  
Vol 125 (9) ◽  
pp. 2185-2197 ◽  
Author(s):  
D. J. Toth ◽  
J. T. Toth ◽  
G. Gulyas ◽  
A. Balla ◽  
T. Balla ◽  
...  

2007 ◽  
Vol 18 (8) ◽  
pp. 2960-2969 ◽  
Author(s):  
Xiaoshan Jiang ◽  
Jeffrey L. Benovic ◽  
Philip B. Wedegaertner

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.


Endocrinology ◽  
2007 ◽  
Vol 148 (7) ◽  
pp. 3236-3245 ◽  
Author(s):  
E. Filardo ◽  
J. Quinn ◽  
Y. Pang ◽  
C. Graeber ◽  
S. Shaw ◽  
...  

G protein-coupled receptor 30 (GPR30), a seven-transmembrane receptor (7TMR), is associated with rapid estrogen-dependent, G protein signaling and specific estrogen binding. At present, the subcellular site of GPR30 action is unclear. Previous studies using antibodies and fluorochrome-labeled estradiol (E2) have failed to detect GPR30 on the cell surface, suggesting that GPR30 may function uniquely among 7TMRs as an intracellular receptor. Here, we show that detectable expression of GPR30 on the surface of transfected HEK-293 cells can be selected by fluorescence-activated cell sorting. Expression of GPR30 on the cell surface was confirmed by confocal microscopy using the lectin concanavalin A as a plasma membrane marker. Stimulation of GPR30-expressing HEK-293 cells with 17β-E2 caused sequestration of GPR30 from the cell surface and resulted in its codistribution with clathrin and mobilization of intracellular calcium stores. Evidence that GPR30 signals from the cell surface was obtained from experiments demonstrating that the cell-impermeable E2-protein conjugates E2-BSA and E2-horseradish peroxidase promote GPR30-dependent elevation of intracellular cAMP concentrations. Subcellular fractionation studies further support the plasma membrane as a site of GPR30 action with specific [3H]17β-E2 binding and G protein activation associated with plasma membrane but not microsomal, or other fractions, prepared from HEK-293 or SKBR3 breast cancer cells. These results suggest that GPR30, like other 7TMRs, functions as a plasma membrane receptor.


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