Stimuli which act through the second messenger inositol 1,4,5- trisphosphate (InsP3) often increase free intracellular Ca2+ concentration ([Ca2+](i)) in a localized subcellular area. Actively propagated Ca2+ waves then extend this focal Ca2+ signal to other parts of the cell. To understand how cells may control the spatial distribution of Ca2+, we investigated the mechanism by which Ca2+ waves propagate through the cytoplasm of Xenopus oocytes. Heparin, which inhibits the binding of InsP3 to its receptor, prevented the migration of Ca2+ waves induced by a poorly metabolized InsP3 (InsP3S3). This result suggested that Ca2+ waves move through the cell via the serial release of Ca2+ from InsP3-sensitive stores. Interventions which caused a localized increase in [Ca2+](i) without elevations of InsP3 did not trigger Ca2+ waves. In the presence of a InsP3S3, however, endogenously released or locally injected Ca2+ elicited Ca2+ waves. A cooperative interaction between Ca2+ and InsP3 may therefore be responsible for the propagation of Ca2+ waves.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - Jan 1 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology