Effects of pertussis toxin-catalyzed ADP-ribosylation on interactions of transducin and the inhibitory GTP-binding protein of adenylate cyclase with guanyl nucleotides |
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| Authors: | P Bruni E L Hewlett J Moss |
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| Institution: | 3. Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20205, USA;4. Departments of Medicine and Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA |
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| Abstract: | Release of bound 3H]Gpp(NH)p from NG108-15 cell membranes was induced by carbamylcholine, enkephalinamide, and norepinephrine, all of which inhibit adenylate cyclase. Release was blocked by antagonist, was greater with multiple agonists than with one, and required guanyl nucleotides. With membranes from pertussis toxin-treated cells, both total 3H] Gpp(NH)p binding and agonist-induced 3H]Gpp(NH)p release was decreased. ADP-ribosylation by toxin of transducin, the retinal GTP-binding protein which is similar in structure and function to that in cyclase, decreased 3H]Gpp(NH)p binding. Thus, the inability to demonstrate agonist-induced 3H]Gpp(NH)p release from toxin-treated NG108-15 membranes may result in part from absence of bound 3H]Gpp(NH)p. |
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| Keywords: | Gpp(NH)p guanyl-5-yl-β γ-imidodiphosphate App(NH)p adenyl-5-yl-β γ-imidodiphosphate EGTA ethylene glycol bis (β-aminoethyl ether)-N N N′ N′-tetraacetic acid buffer A the stimulatory GTP-binding protein of cyclase the inhibitory GTP-binding protein of cyclase |
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