Oligomeric potential of the M2 muscarinic cholinergic receptor.
G protein-coupled receptors are known to exist as oligomers. Although such aggregates often are referred to as dimers, there is little direct evidence regarding their oligomeric size. In the present investigation, c-Myc-, FLAG-, and influenza hemagglutinin (HA)-tagged forms of the M2 muscarinic receptor have been coexpressed in Sf9 cells to probe for aggregates larger than a dimer. Immunochromatography, immunoprecipitation, and immunoblotting were carried out with various combinations of antibodies directed against the different epitopes to demonstrate that all three tagged forms of the receptor can be immunopurified within a single complex. Extracts of the M2 muscarinic receptor from Sf9 cells therefore contain aggregates that are at least trimeric, and the levels detected point to the existence of larger complexes. The data also suggest that the oligomers coexist with a sizeable population of monomers.
Park
Paul S-H
PS
Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
Wells
James W
JW
D000818:Animals; D000918:Antibody Specificity; D015153:Blotting, Western; D002460:Cell Line; D000939:Epitopes / Q000235:genetics; D006801:Humans; D015151:Immunoblotting; D046911:Macromolecular Substances; D011233:Precipitin Tests; D011485:Protein Binding / Q000502:physiology; D043585:Receptor, Muscarinic M2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera
D000939:Epitopes; D046911:Macromolecular Substances; D043585:Receptor, Muscarinic M2; D011993:Recombinant Fusion Proteins