Activation of a variety of cell surface receptors results in a biphasic increase in the cytoplasmic Ca2+ concentration, due to the release, or mobilization, of intracellular Ca2+ stores and to the entry of Ca2+ from the extracellular space. Stimulation of these same receptors also results in the phospholipase-C-catalysed hydrolysis of the minor plasma membrane phospholipid, phosphatidylinositol 4,5-bisphosphate, with the concomitant formation of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and diacylglycerol. Analogous to the adenylyl cyclase signalling system, receptor-mediated stimulation of phospholipase C also appears to occur through one or more intermediary guanine nucleotide-dependent regulatory proteins. It is well established that phosphatidylinositol 4,5-bisphosphate hydrolysis is responsible for the changes in Ca2+ homeostasis. There is strong evidence that Ins(1,4,5)P3 stimulates Ca2+ release from intracellular stores. The Ca2+-releasing actions of Ins(1,4,5)P3 are terminated by its metabolism through two distinct pathways. Ins(1,4,5)P3 is dephosphorylated by a 5-phosphatase to Ins(1,4)P2; alternatively, Ins(1,4,5)P3 can also be phosphorylated to Ins(1,3,4,5)P4 by a 3-kinase. Whereas the mechanism of Ca2+ mobilization is understood, the precise mechanisms involved in Ca2+ entry are not known; a recent proposal that Ins(1,4,5)P3 by emptying an intracellular Ca2+ pool, secondarily elicits Ca2+ entry will be considered. This review summarizes our current understanding of the mechanisms by which inositol phosphates regulate cytoplasmic Ca2+ concentrations.
Skip Nav Destination
JOURNAL ARTICLE| 01 September 1988
The role of phosphoinositide metabolism in signal transduction in secretory cells
J. W. Putney
Calcium Regulation Section, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
Online Issn: 1477-9145
Print Issn: 0022-0949
© 1988 by Company of Biologists
J Exp Biol (1988) 139 (1): 135–150.
- Views Icon Views
- PDF LinkPDF
- Share Icon Share
- Search Site
J. W. Putney; The role of phosphoinositide metabolism in signal transduction in secretory cells. J Exp Biol 1 September 1988; 139 (1): 135–150. doi: https://doi.org/10.1242/jeb.139.1.135
Download citation file: