TUBULAR MEMBRANE INVAGINATIONS COATED BY DYNAMIN RINGS ARE INDUCED BY GTP-GAMMA-S IN NERVE-TERMINALS
TUBULAR MEMBRANE INVAGINATIONS COATED BY DYNAMIN RINGS ARE INDUCED BY GTP-GAMMA-S IN NERVE-TERMINALS
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DOI：
10.1038/374186a0
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发表时间：
1995-03-09
期刊：
影响因子：
64.8
通讯作者：
DECAMILLI, P
中科院分区：
文献类型：
--
作者：
TAKEI, K;MCPHERSON, PS;DECAMILLI, P
突触囊泡膜在胞吐作用后重新内化的机制仍有争议（1-5）。由于几个囊泡运输步骤需要GTP水解（6-9），GTP-γ S可能有助于识别突触囊泡再循环中的中间体。在GTP-γ S处理的神经末梢中，我们观察到质膜的管状内陷，其通常但不总是被网格蛋白包被的芽覆盖。引人注目的是，这些小管的壁被横向电子致密环装饰，其在形态上类似于由管状模板周围的发动蛋白形成的结构（10，11）。发动蛋白是一种涉及突触囊泡内吞作用的GT蛋白（12-14），在这里，我们表明这些膜小管的壁，而不是它们的远端，对发动蛋白免疫反应性呈阳性。这些发现表明，发动蛋白和网格蛋白在形成内吞囊泡的不同位点起作用，他们强烈支持在裂变反应中发动蛋白的作用，并建议稳定的GTP-发动蛋白的结合构象通过囊泡柄的逐渐伸长导致小管形成。
THE mechanisms through which synaptic vesicle membranes are reinternalized after exocytosis remain a matter of debate(1-5). Because several vesicular transport steps require GTP hydrolysis(6-9), GTP-gamma S may help identify intermediates in synaptic vesicle recycling. In GTP-gamma S-treated nerve terminals, we observed tubular invaginations of the plasmalemma that were often, but not always, capped by a clathrin-coated bud, Strikingly, the walls of these tubules were decorated by transverse electron-dense rings that were morphologically similar to structures formed by dynamin around tubular templates(10,11). Dynamin is a GTPase implicated in synaptic vesicle endocytosis(12-14) and here we show that the wails of these membranous tubules, but not their distal ends, were positive for dynamin immunoreactivity, These findings demonstrate that dynamin and clathrin act at different sites in the formation of endocytic vesicles, They strongly support a role for dynamin in the fission reaction and suggest that stabilization of the GTP-bound conformation of dynamin leads to tubule formation by progressive elongation of the vesicle stalk.