Regulation of cortical vesicle exocytosis in sea urchin eggs by inositol 1,4,5-trisphosphate and GTP-binding protein.
Regulation of cortical vesicle exocytosis in sea urchin eggs by inositol 1,4,5-trisphosphate and GTP-binding protein.
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肌醇 1,4,5-三磷酸和 GTP 结合蛋白对海胆卵皮质囊泡胞吐作用的调节。
DOI：
10.1083/jcb.102.1.70
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Fein,A
中科院分区：
文献类型：
--
作者：
Turner,PR;Jaffe,LA;Fein,A
为了研究海胆卵中肌醇1，4，5-三磷酸(InsP3)和鸟苷核苷酸结合蛋白(G-蛋白)在海胆卵皮质囊泡受精与胞吐耦合的转导机制中的作用，我们将InsP3和鸟苷核苷酸类似物显微注射到海胆卵中。注射28 nM InsP3可引起胞吐。然而，如果卵子首先注射EGTA([CaI]小于或等于0.1微米；EGTA=1.6 mM)，InsP3注射不会引起胞吐，支持InsP3通过引起细胞内游离钙升高而起作用的假设。注射28微米的鸟苷-5‘-0-(3-硫代三磷酸)(GTP-伽马-S)，引起胞吐，但如果预先注射EGTA，则不会发生胞吐。注射代谢稳定的国内生产总值类似物3 mM鸟苷-5‘-0-(2-硫代二磷酸)(国内生产总值-β-S)可阻止精子刺激胞吐。然而，注射GDPβ-S并不能阻止InsP3对胞吐的刺激。这些结果表明发生了以下一系列事件。精子激活一种G蛋白，从而刺激InsP3的产生。InsP3升高细胞内游离钙，导致胞吐。
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 ([Cai] less than or equal to 0.1 microM; 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 microM guanosine-5'-0-(3-thiotriphosphate) (GTP-gamma-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'-0-(2-thiodiphosphate) (GDP-beta-S), a metabolically stable analog of GDP, prevented sperm from stimulating exocytosis. However, injection of GDP-beta-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.