| Abstract: | A biochemical pathway to platelet activation involving protein kinase C has been deemed "Ca2+-independent", because the intracellular fluorophore quin2 indicates no rise in cytoplasmic Ca2+] in platelets stimulated by certain agonists. However, unlike quin2, the Ca2+-sensitive photoprotein aequorin demonstrates a rise in Ca2+] when platelet aggregation is induced by phorbol ester or diacylglycerol. Aequorin and quin2 appear to report different aspects of Ca2+ homeostasis, and the absence of a quin2 signal may not be sufficient to establish that a metabolic pathway is "Ca2+-independent". |
