The alpha2A-adrenergic receptor discriminates between Gi heterotrimers of different betagamma subunit composition in Sf9 insect cell membranes.
In view of the expanding roles of the betagamma subunits of the G proteins in signaling, the possibility was raised that the rich diversity of betagamma subunit combinations might contribute to the specificity of signaling at the level of the receptor. To test this possibility, Sf9 cell membranes expressing the recombinant alpha2A-adrenergic receptor were used to assess the contribution of the betagamma subunit composition. Reconstituted coupling between the receptor and heterotrimeric Gi protein was assayed by high affinity, guanine nucleotide-sensitive binding of the alpha2-adrenergic agonist, [3H]UK-14,304. Supporting this hypothesis, the present study showed clear differences in the abilities of the various betagamma dimers, including those containing the beta3 subtype and the newly described gamma4, gamma10, and gamma11 subtypes, to promote interaction of the same alphai subunit with the alpha2A-adrenergic receptor.
Richardson
M
M
Henry Hood Research Program, Pennsylvania State University College of Medicine, Weis Center for Research, Danville, Pennsylvania 17822-2614, USA.
Robishaw
J D
JD
D058647:Adrenergic alpha-2 Receptor Agonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001704:Biopolymers; D000068438:Brimonidine Tartrate; D002462:Cell Membrane / Q000378:metabolism; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011810:Quinoxalines / Q000494:pharmacology; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*; D018411:Spodoptera
D058647:Adrenergic alpha-2 Receptor Agonists; D000316:Adrenergic alpha-Agonists; D001704:Biopolymers; D011810:Quinoxalines; D018341:Receptors, Adrenergic, alpha-2; D000068438:Brimonidine Tartrate; D019206:GTP-Binding Protein alpha Subunits, Gi-Go