A Rho-related GTPase is involved in Ca2+-dependent neurotransmitter exocytosis
A Rho-related GTPase is involved in Ca2+-dependent neurotransmitter exocytosis
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DOI：
10.1074/jbc.275.11.7764
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发表时间：
2000-03-17
影响因子：
4.8
通讯作者：
Poulain, B
中科院分区：
文献类型：
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作者：
Doussau, F;Gasman, S;Poulain, B
Rho、Rac 和 Cdc42 单体 GTP 酶是众所周知的肌动蛋白细胞骨架和磷酸肌醇代谢的调节因子，并且与内分泌细胞的激素分泌有关。在这里，我们研究了它们在 Ca2+ 依赖性神经递质胞吐作用中的可能含义。使用亚细胞分级分离程序，我们发现大鼠脑突触体中存在 RhoA、RhoB、Rac1 和 Cdc42；然而，只有 Rad 与高度纯化的突触小泡有关。为了确定这些 GTP 酶的突触功能，将损害 Rho 相关蛋白的毒素显微注射到海兔神经元中。我们使用来自索氏梭菌的致命毒素，它可以使 Rac 失活；来自艰难梭菌的毒素 B，可灭活 Rho、Rac 和 Cdc42；来自梭菌的 C3 外切酶；来自大肠杆菌的肉毒杆菌和细胞毒性坏死因子 1，主要影响 Rho。对毒素对乙酰胆碱释放的影响的分析表明，Rho 家族的一个成员（很可能是 Rad）参与了神经递质释放的控制。引人注目的是，致命毒素和毒素 B 对乙酰胆碱释放的阻碍可以在
Rho, Rac, and Cdc42 monomeric GTPases are well known regulators of the actin cytoskeleton and phosphoinositide metabolism and have been implicated in hormone secretion in endocrine cells. Here, we examine their possible implication in Ca2+-dependent exocytosis of neurotransmitters. Using subcellular fractionation procedures, we found that RhoA,RhoB, Rac1, and Cdc42 are present in rat brain synaptosomes; however, only Rad was associates with highly purified synaptic vesicles. To determine the synaptic function of these GTPases, toxins that impair Rho-related proteins were microinjected into Aplysia neurons. We used lethal toxin from Clostridium sordellii, which inactivates Rac; toxin B from Clostridium difficile, which inactivates Rho, Rac, and Cdc42; and C3 exoenzyme from Clostridium bo;botulinum and cytotoxic necrotizing factor 1 from Escherichia coli, which mainly affect Rho. Analysis of the toxin effects on evoked acetylcholine release revealed that a member of the Rho family, most likely Rad, was implicated in the control of neurotransmitter release. Strikingly, blockage of acetylcholine release by lethal toxin and toxin B could be completely removed in