Possible interaction of alpha 1-adrenergic receptor with pertussis-toxin-sensitive guanine-nucleotide-binding regulatory proteins (G proteins) responsible for phospholipase C activation in rat liver plasma membranes.
Islet-activating protein (IAP; pertussis toxin) was employed to test the hypothesis that IAP-sensitive GTP-binding regulatory proteins (G proteins) are coupled with alpha 1-adrenergic receptor in rat liver plasma membranes. The high-affinity state of the binding of alpha 2-adrenergic agonist, which is known to be coupled with IAP-sensitive G protein, was abolished in IAP-treated plasma membranes. IAP treatment of plasma membranes could also diminish the high-affinity state of the alpha 1-adrenergic receptor for the agonist. Restoration of the high-affinity state of the alpha 1-adrenergic receptor for the agonist occurred on reconstitution of the bovine brain IAP-sensitive G proteins. The alpha 1-adrenergic receptor agonist stimulated inositol triphosphate (InsP3) production from [3H]inositol-labeled liver plasma membranes in a concentration-dependent manner. IAP treatment also decreased alpha 1-adrenergic-agonist-induced InsP3 production but not completely. From these results, we concluded that there is a possibility that both IAP-sensitive and IAP-insensitive G proteins were involved in alpha 1-adrenergic-receptor-stimulated phospholipase C activation in rat liver plasma membranes.
Tohkin
M
M
Shionogi Research Laboratories, Shionogi & Co. Ltd, Osaka, Japan.
Yagami
T
T
Katada
T
T
Matsubara
T
T
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D037342:Pertussis Toxin; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D015016:Yohimbine / Q000378:metabolism
D011942:Receptors, Adrenergic, alpha; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D015016:Yohimbine; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D015544:Inositol 1,4,5-Trisphosphate; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D011224:Prazosin