Regulation of cortical vesicle exocytosis in sea urchin eggs by inositol 1,4,5-trisphosphate and GTP-binding protein

156Citations
Citations of this article
16Readers
Mendeley users who have this article in their library.
Get full text

Abstract

To investigate the roles of inositol 1,4,5-trisphosphate (InsP3) and guanyl nucleotide binding proteins (G-proteins) in the transduction mechanism coupling fertilization and exocytosis of cortical vesicles in sea urchin eggs, we microinjected InsP3 and guanyl nucleotide analogs into eggs of Lytechinus variegatus. Injection of 28 nM InsP3 caused exocytosis. However, if the egg was first injected with EGTA ([Ca(i)] ≤ 0.1 μM; EGTA = 1.6 mM), InsP3 injection did not cause exocytosis, supporting the hypothesis that InsP3 acts by causing a rise in intracellular free calcium. Injection of 28 μM guanosine-5'-O-(3-thiotriphosphate) (GTP-γ-S), a hydrolysis-resistant analog of GTP, caused exocytosis, but exocytosis did not occur if the egg was pre-injected with EGTA. Injection of 3 mM guanosine-5'-O-(2-thiodiphosphate) (GDP-β-S), a metabolically stable analog of GDP, prevented sperm from stimulating exocytosis. However, injection of GDP-β-S did not prevent the stimulation of exocytosis by InsP3. These results suggested the following sequence of events. The sperm activates a G-protein, which stimulates production of InsP3. InsP3 elevates intracellular free calcium, which causes exocytosis.

Cite

CITATION STYLE

APA

Turner, P. R., Jaffe, L. A., & Fein, A. (1986). Regulation of cortical vesicle exocytosis in sea urchin eggs by inositol 1,4,5-trisphosphate and GTP-binding protein. Journal of Cell Biology, 102(1), 70–76. https://doi.org/10.1083/jcb.102.1.70

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free