We have investigated the subcellular distribution and identity of inositol trisphosphate (InsP3)-sensitive calcium stores in living Limulus ventral photoreceptor cells, where light and InsP3 are known to raise intracellular calcium. We injected ventral photoreceptor cells with the photoprotein aequorin and viewed its luminescence with an image intensifier. InsP3 only elicited detectable aequorin luminescence when injected into the light-sensitive rhabdomeral (R)-lobe where aequorin luminescence induced by light was also confined. Calcium stores released by light and InsP3 are therefore localized to the R-lobe. Within the R-lobe, InsP3-induced aequorin luminescence was further confined around the injection site, due to rapid dilution and/or degradation of injected InsP3. Prominent cisternae of smooth endoplasmic reticulum are uniquely localized within the cell beneath the microvillar surface of the R-lobe (Calman, B., and S. Chamberlain, 1982, J. Gen. Physiol., 80:839-862). These cisternae are the probable site of InsP3 action.
Article| April 01 1987
Inositol 1,4,5 trisphosphate releases calcium from specialized sites within Limulus photoreceptors
Online Issn: 1540-8140
Print Issn: 0021-9525
J Cell Biol (1987) 104 (4): 933–937.
- Views Icon Views
- PDF LinkPDF
- Share Icon Share
- Search Site
R Payne, A Fein; Inositol 1,4,5 trisphosphate releases calcium from specialized sites within Limulus photoreceptors. J Cell Biol 1 April 1987; 104 (4): 933–937. doi: https://doi.org/10.1083/jcb.104.4.933
Download citation file: