Bombesin and thrombin affect discrete pools of intracellular calcium through different G-proteins.
In mouse NIH 3T3 cells, the mitogens bombesin and thrombin induced Ca2+ release from intracellular stores. Ca2+ release induced by bombesin was inhibited by the Ca(2+)-ATPase inhibitor thapsigargin, while Ca2+ release induced by thrombin was unaffected by this agent. The Ca(2+)-release response to bombesin was not affected by pertussis toxin, but the response to thrombin was abolished by the toxin. Stable transfectants overexpressing the G-protein subunit type alpha 9 showed an accentuated response to bombesin, indicating that the bombesin receptor was coupled to a Gq-like G-protein. Together, these results show that the two mitogenic receptors are coupled to distinct G-proteins that affect functionally different pools of Ca2+. Organization of signalling pathways in this manner may allow cells to differentially encode information from different signals.
Wang
J L
JL
Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA.
Kalyanaraman
S
S
Vivo
M D
MD
Gautam
N
N
D016475:3T3 Cells; D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D051379:Mice; D037342:Pertussis Toxin; D018004:Receptors, Bombesin / Q000378:metabolism; D015398:Signal Transduction; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D018004:Receptors, Bombesin; D010566:Virulence Factors, Bordetella; D019284:Thapsigargin; D015544:Inositol 1,4,5-Trisphosphate; D037342:Pertussis Toxin; D013917:Thrombin; D019204:GTP-Binding Proteins; D000252:Calcium-Transporting ATPases; D001839:Bombesin; D002118:Calcium