Receptor availability defines the extent of agonist-mediated G-protein down-regulation in neuroblastoma x glioma hybrid cells transfected to express the beta 2-adrenoceptor.
Sustained exposure of neuroblastoma x glioma hybrid, NG108-15, cells transfected to express the human beta 2-adrenoceptor (clone beta N22) to isoprenaline or iloprost (an agonist at the endogenously expressed IP prostanoid receptor) resulted in a substantial and selective down-regulation of the alpha subunit of the G-protein Gs. Treatment of these cells with the irreversible beta-adrenoceptor antagonist bromoacetyl alprenolol menthane diminished both the potency and the maximal ability of isoprenaline but not of iloprost to cause Gs alpha down-regulation. These results demonstrate that the extent of agonist-mediated Gs alpha down-regulation is dependent upon the availability of receptor to agonist.
Kim
G D
GD
Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK.
Milligan
G
G
D000262:Adenylyl Cyclases / Q000378:metabolism; D058672:Adrenergic beta-2 Receptor Antagonists; D000526:Alprenolol / Q000031:analogs & derivatives / Q000494:pharmacology; D015536:Down-Regulation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015870:Gene Expression; D005910:Glioma / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells / Q000187:drug effects / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D009447:Neuroblastoma / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D058672:Adrenergic beta-2 Receptor Antagonists; D018343:Receptors, Adrenergic, beta-2; C045331:bromoacetylalprenololmenthane; D000526:Alprenolol; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D007545:Isoproterenol