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 Ca2+-ATPase inhibitor thapsigargin, while Ca2+ release induced by thrombin was unaffected by this agent. The Ca2+-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 αq 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.
Bombesin and thrombin affect discrete pools of intracellular calcium through different G-proteins
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Jin-Lin WANG, Somasundaram KALYANARAMAN, Michael DE VIVO, Narasimhan GAUTAM; Bombesin and thrombin affect discrete pools of intracellular calcium through different G-proteins. Biochem J 15 November 1996; 320 (1): 87–91. doi: https://doi.org/10.1042/bj3200087
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