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Nature:突触囊泡的快速重构

标签:突触囊泡
摘要 : 自从突触囊泡循环在上个世纪70年代被发现以来,网格蛋白(clathrin)一直被认为在质膜上发挥作用,在轴突末端受到刺激后约20秒来重构突触囊泡。Erik Jorgensen及同事重做了当初的那些实验,但将光遗传学刺激与高压冷冻相结合来在刺激之后将样本迅速固定。

nature13846-sf1 

自从突触囊泡循环在上个世纪70年代被发现以来,网格蛋白(clathrin)一直被认为在质膜上发挥作用,在轴突末端受到刺激后约20秒来重构突触囊泡。Erik Jorgensen及同事重做了当初的那些实验,但将光遗传学刺激与高压冷冻相结合来在刺激之后将样本迅速固定。这样做便使情况发生了改变:以前假设的机制在22°C这个非生理性的、“室温”温度下有效,这个时候超快内吞作用被中断。

在某一生理温度下 (34°C),大囊泡则会在大约50毫秒内通过独立于网格蛋白的超快内吞作用被从质膜中提取出来;这些囊泡然后会融合形成核内体,在刺激之后大约5秒小囊泡会通过网格蛋白支架从它们当中被再生出来。

原文摘要:

Clathrin regenerates synaptic vesicles from endosomes

Shigeki Watanabe, Thorsten Trimbuch, Marcial Camacho-Pérez, Benjamin R. Rost, Bettina Brokowski, Berit Söhl-Kielczynski, Annegret Felies, M. Wayne Davis, Christian Rosenmund & Erik M. Jorgensen

Abstract: Ultrafast endocytosis can retrieve a single, large endocytic vesicle as fast as 50–100 ms after synaptic vesicle fusion. However, the fate of the large endocytic vesicles is not known. Here we demonstrate that these vesicles transition to a synaptic endosome about one second after stimulation. The endosome is resolved into coated vesicles after 3 s, which in turn become small-diameter synaptic vesicles 5–6 s after stimulation. We disrupted clathrin function using RNA interference (RNAi) and found that clathrin is not required for ultrafast endocytosis but is required to generate synaptic vesicles from the endosome. Ultrafast endocytosis fails when actin polymerization is disrupted, or when neurons are stimulated at room temperature instead of physiological temperature. In the absence of ultrafast endocytosis, synaptic vesicles are retrieved directly from the plasma membrane by clathrin-mediated endocytosis. These results may explain discrepancies among published experiments concerning the role of clathrin in synaptic vesicle endocytosis.(doi: 10.1038/nature13846 & doi:10.1038/nature13925

对应Nature杂志: 2014年11月13日Nature杂志精选

来源: Nature中文 浏览次数:79

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