title: Pertussis toxin inhibits enkephalin stimulation of GTPase of NG108-15 cells.
abstract: In neuroblastoma-glioma (NG108-15) hybrid cells, opiates inhibit adenylate cyclase and stimulate a low Km GTPase. It has been postulated that the stimulation of GTPase plays a role in opiate inhibition of adenylate cyclase (Koski, G., and Klee, W. A. (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 4185-4189). Treatment of NG108-15 cells with pertussis toxin attenuates receptor-mediated inhibition of adenylate cyclase. The toxin acts by catalyzing the ADP-ribosylation of a 41,000-dalton substrate believed to be a part of the receptor-adenylate cyclase complex. We have found that toxin treatment of NG108-15 results in inhibition of the opiate-stimulated GTPase. The concentration of toxin required for inhibition of this GTPase was similar to that needed for both attenuation of opiate inhibition of adenylate cyclase and ADP ribosylation of the 41,000-dalton substrate. Inhibition of the opiate-induced GTPase by pertussis toxin in isolated membranes required NAD, consistent with the hypothesis that this effect of the toxin resulted from ADP ribosylation of a protein component of the system. Since the opiate-stimulated GTPase is believed to play a role in the receptor-mediated decrease in adenylate cyclase activity, inhibition of this GTPase may be an important part of the mechanism by which the toxin interferes with opiate action on adenylate cyclase.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D037361:Adenylate Cyclase Toxin; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism / Q000494:pharmacology*; D001886:Bordetella pertussis; D002460:Cell Line; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D005910:Glioma / Q000201:enzymology*; D006822:Hybrid Cells / Q000201:enzymology*; D007700:Kinetics; D051379:Mice; D008970:Molecular Weight; D009447:Neuroblastoma / Q000201:enzymology*; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D051381:Rats; D010566:Virulence Factors, Bordetella
chemical_list: D037361:Adenylate Cyclase Toxin; D000700:Analgesics; D001427:Bacterial Toxins; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D004744:Enkephalin, Methionine; C013801:enkephalin-Met, Ala(2)-; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases