Functional coupling of the Galpha(olf) variant XLGalpha(olf) with the human adenosine A2A receptor.
A recently identified novel Galphaolf variant, XLGalphaolf, is shown to functionally couple to the human adenosine A2A receptor (A2AR). In Sf9 cells expressing A2AR, beta1, and gamma2, co-expression of XLGalphaolf increased NECA-induced [35S]GTPgammaS binding from approximately 130% to 300% of basal levels. Pharmacological characteristics of A2AR ligands on these cells were evaluated by using [3H]ZM241385- and [35S]GTPgammaS- binding assays. The rank order of the equilibrium binding constants (Kd or Ki) of adenosine receptor ligands were [3H]ZM241385 approximately CGS15943 < MRS1220 < < CV1808 approximately NECA < CGS21680 approximately adenosine < IBMECA < HEMADO approximately CPA approximately CCPA. The rank order of EC50 values for agonists were CV1808 approximately NECA < adenosine approximately CGS26180 < IBMECA < HEMADO approximately CPA approximately CCPA. This pharmacology is consistent with the literature for A2AR and suggests that Sf9 cells co-expressing A2AR, beta1, gamma2, and XLGalphaolf could serve as a heterologous expression system for A2AR drug screening.
Ravyn
Vipa
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Lead Discovery, AstraZeneca Pharmaceuticals, Wilmington, Delaware 19850, USA.
Bostwick
J Robert
JR
D000241:Adenosine / Q000737:chemistry; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D001667:Binding, Competitive; D002460:Cell Line; D002478:Cells, Cultured; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D007313:Insecta; D007700:Kinetics; D008024:Ligands; D011485:Protein Binding; D043705:Receptor, Adenosine A2A / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry
D044385:GTP-Binding Protein alpha Subunits; D008024:Ligands; D043705:Receptor, Adenosine A2A; D011994:Recombinant Proteins; C084618:olfactory G protein subunit alpha olf; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000241:Adenosine