G proteins in aortic endothelial cells and bradykinin-induced formation of nitric oxide.
In bovine aortic endothelial cells (BAEC), pertussis toxin (PTx) ADP-ribosylated two major substrates with apparent molecular masses of 40 and 41 kDa, whereas cholera toxin (CTx) ADP-ribosylated two other substrates of 44 and 50 kDa. [alpha-32P]GTP bound to three bands in the 22-27 kDa range. Immunoblot analysis revealed the simultaneous presence of G alpha i1, G alpha i2, G alpha i3, G alpha q or G alpha 11 and of different forms of G alpha s but did not detect significant levels of G alpha 0. Bradykinin caused a 9-fold increase in intracellular cyclic GMP level in BAEC (measured as an index of NO production). Preincubation of BAEC with CTx, but not with PTx, inhibited bradykinin-dependent production of cyclic GMP. These results show that G alpha s, G alpha q or alpha 11, Gi and small GTP-binding proteins are present in BAEC and suggest that a CTx-sensitive G-protein (possibly either small G-protein, G alpha q or G alpha 11) could be associated with the bradykinin-mediated NO formation.
Gil-Longo
J
J
Laboratoire de Pharmacologie Cellulaire et Moléculaire, Université Louis Pasteur de Strasbourg, Illkirch, France.
Dufour
M N
MN
Guillon
G
G
Lugnier
C
C
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001920:Bradykinin / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D006152:Cyclic GMP / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D015151:Immunoblotting; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D009569:Nitric Oxide; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D006152:Cyclic GMP; D001920:Bradykinin