Elementary calcium-release units induced by inositol trisphosphate.
The extent to which inositol 1,4,5-trisphosphate (InsP3)-induced calcium signals are localized is a critical parameter for understanding the mechanism of effector activation. The spatial characteristics of InsP3-mediated calcium signals were determined by targeting a dextran-based calcium indicator to intracellular membranes through the in situ addition of a geranylgeranyl lipid group. Elementary calcium-release events observed with this indicator typically lasted less than 33 milliseconds, had diameters less than 2 micrometers, and were uncoupled from each other by the calcium buffer EGTA. Cellwide calcium transients are likely to result from synchronized triggering of such local release events, suggesting that calcium-dependent effector proteins could be selectively activated by localization near sites of local calcium release.
Horne
J H
JH
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
Meyer
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D018274:Electroporation; D005456:Fluorescent Dyes; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000378:metabolism*; D007700:Kinetics; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009930:Organic Chemicals; D010455:Peptides / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D005456:Fluorescent Dyes; D009930:Organic Chemicals; D010455:Peptides; C071336:calcium green; D004533:Egtazic Acid; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium