title: Cholera toxin ADP-ribosylates the receptor-coupled form of pertussis toxin-sensitive G-proteins.
abstract: Cholera toxin catalyzes the ADP-ribosylation of 40 kDa pertussis toxin substrates in membranes from NG108-15 cells, which is increased in the presence of the opioid agonist DADLE. The basal ADP-ribosylation can be abolished by the opioid antagonist ICI 174864, suggesting that unoccupied opioid receptors interact spontaneously with the pertussis toxin substrates Gi/Go in the membrane. Treatment of NG108-15 cells with the opioid agonist DADLE leads to a reduction of agonist-stimulated and basal ADP-ribosylation of 40 kDa substrates catalyzed by cholera toxin. This indicates that the spontaneous interaction between opioid receptors and G-proteins is decreased in membranes of cells in which the receptor was desensitized by prolonged exposure to the agonist.
authors.affiliation: Department of Neuropharmacology, Max-Planck-Institut für Psychiatrie, Planegg-Martinsried, F.R.G.
authors.forename: F J
authors.initials: FJ
authors.lastname: Klinz
authors.forename: T
authors.initials: T
authors.lastname: Costa
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002772:Cholera Toxin / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005910:Glioma; D006822:Hybrid Cells / Q000378:metabolism; D009243:NAD / Q000378:metabolism*; D009447:Neuroblastoma; D037342:Pertussis Toxin; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
chemical_list: D011957:Receptors, Opioid; D010566:Virulence Factors, Bordetella; D009243:NAD; D000246:Adenosine Diphosphate Ribose; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D002772:Cholera Toxin; D037342:Pertussis Toxin; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins