title: Pertussis and cholera toxin ADP-ribosylation in Dictyostelium discoideum membranes.
abstract: We report a 39 kDa substrate for cholera and pertussis toxins is present in D. discoideum membranes. This protein did not co-migrate with alpha subunits of either Gs (45 kDa and 52 kDa) or Gi (41 kDa) from control mammalian cells. The presence of GTP or its non-hydrolyzable analogs enhanced the ADP-ribosylation in response to cholera toxin, but did not significantly alter ADP-ribosylation by pertussis toxin. Divalent cations inhibited the ADP-ribosylation by both toxins. The possible association of this novel G-protein with D. discoideum adenylate cyclase may underlie some of the unique regulatory features of this enzyme. Alternatively, this G-protein may regulate one of several other cellular responses mediated by the cAMP receptor.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000096:biosynthesis*; D037361:Adenylate Cyclase Toxin; D002462:Cell Membrane / Q000378:metabolism*; D002772:Cholera Toxin / Q000378:metabolism / Q000494:pharmacology*; D004023:Dictyostelium / Q000187:drug effects*; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D037361:Adenylate Cyclase Toxin; D005656:Fungal Proteins; D008565:Membrane Proteins; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins