Association of Rab3A with synaptic vesicles at late stages of the secretory pathway.
Association of Rab3A with synaptic vesicles at late stages of the secretory pathway.
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DOI：
10.1083/jcb.115.3.625
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发表时间：
1991-11
影响因子：
7.8
通讯作者：
De Camilli, P
中科院分区：
文献类型：
--
作者：
Matteoli, M;Takei, K;Cameron, R;Hurlbut, P;Johnston, P A;Sudhof, T C;Jahn, R;De Camilli, P
Rab3A是一种小的GTP结合蛋白，高度集中在突触小泡上。像其他小的GTP结合蛋白一样，它被认为在可溶状态和膜结合状态之间循环。为了确定突触囊泡Rab3A在生命周期的哪个阶段与其膜相关，我们研究了该蛋白在不同发育和功能阶段的神经元和神经内分泌细胞中的定位。在所有病例中，Rab3A与突触小泡标记共同定位于细胞外围，但在高尔基体区缺失，这表明Rab3A与高尔基复合体远侧的小泡结合，并在它们循环到该区域之前从囊泡膜上解离。在青蛙运动终板上进行的免疫荧光实验表明，突触小泡的大量胞吐伴随着Rab3A的移位到细胞表面。在突触小泡与质膜融合之前，Rab3A在突触小泡上的选择性定位表明，该蛋白是一个调节机制的一部分，该机制被组装到小泡上，为胞吐作用做准备。
Rab3A is a small GTP-binding protein highly concentrated on synaptic vesicles. Like other small GTP-binding proteins it is thought to cycle between a soluble and a membrane-associated state. To determine at which stage of the life cycle of synaptic vesicles rab3A is associated with their membranes, the localization of the protein in neurons and neuroendocrine cells at different developmental and functional stages was investigated. In all cases, rab3A was colocalized with synaptic vesicle markers at the cell periphery, but was absent from the Golgi area, suggesting that rab3A associates with vesicles distally to the Golgi complex and dissociates from vesicle membranes before they recycle to this region. Immunofluorescence experiments carried out on frog motor end plates demonstrated that massive exocytosis of synaptic vesicles is accompanied by a translocation of rab3A to the cell surface. The selective localization of rab3A on synaptic vesicles at stages preceding their fusion with the plasmalemma suggests that the protein is part of a regulatory machinery that is assembled onto the vesicles in preparation for exocytosis.