Oligomerization of G-protein-coupled receptors shown by selective co-immunoprecipitation.
Recent studies have shown that G-protein-coupled receptors (GPCRs) can assemble as high molecular weight homo- and hetero-oligomeric complexes. This can result in altered receptor-ligand binding, signaling, or intracellular trafficking. We have co-transfected HEK-293 cells with differentially epitope-tagged GPCRs from different subfamilies and determined whether oligomeric complexes were formed by co-immunoprecipitation and immunoblot analysis. This gave the surprising result that the 5HT(1A) receptor was capable of forming hetero-oligomers with all GPCRs tested including the 5HT(1B), 5HT(1D), EDG(1), EDG(3), GPR(26), and GABA(B2) receptors. The testing of other GPCR combinations showed similar results with hetero-oligomer formation occurring for the 5HT(1D) with the 5HT(1B) and EDG(1) receptor. Control studies showed that these complexes were present in co-transfected cells before the time of lysis and that the hetero-oligomers were comprised of GPCRs at discrete stoichiometries. These findings suggest that GPCRs have a natural tendency to form oligomers when co-transfected into cells. Future studies should therefore investigate the presence and physiological role of GPCR hetero-oligomers in cells in which they are endogenously expressed.
Salim
Kamran
K
Neuroscience Research Centre, Merck Sharp & Dohme Research Laboratories, Harlow, Essex CM20 2QR, United Kingdom. kamran_salim@merck.com
Fenton
Tim
T
Bacha
Jamil
J
Urien-Rodriguez
Hector
H
Bonnert
Tim
T
Skynner
Heather A
HA
Watts
Emma
E
Kerby
Julie
J
Heald
Anne
A
Beer
Margaret
M
McAllister
George
G
Guest
Paul C
PC
D002460:Cell Line; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007668:Kidney; D016297:Mutagenesis, Site-Directed; D021122:Protein Subunits; D016271:Proto-Oncogene Proteins c-myc / Q000737:chemistry; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D044263:Receptors, Serotonin, 5-HT1; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D014162:Transfection
C470302:HTR1B protein, human; D021122:Protein Subunits; D016271:Proto-Oncogene Proteins c-myc; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011956:Receptors, Cell Surface; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D011994:Recombinant Proteins; D019204:GTP-Binding Proteins