Rapid Fusion of Synaptic Vesicles with Reconstituted Target SNARE Membranes
Rapid Fusion of Synaptic Vesicles with Reconstituted Target SNARE Membranes
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DOI：
10.1016/j.bpj.2013.03.038
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发表时间：
2013-05-07
影响因子：
3.4
通讯作者：
Tamm, Lukas K.
中科院分区：
文献类型：
--
作者：
Kiessling, Volker;Ahmed, Saheeb;Tamm, Lukas K.
神经元突触的神经递质释放发生在1 ms或更短的时间尺度上。从纯化的突触蛋白和脂质中重构囊泡融合在阐明突触胞吐融合机制中发挥了重要作用，其细节越来越多。然而，大多数重建方法的一个局限性是在这些系统中产生的融合速率相对较慢。在一项相关研究中，一个值得注意的例外是测量携带囊泡融合蛋白突触泡蛋白的单个重建囊泡与携带突触前质膜蛋白突触融合蛋白和SNAP-25的支撑平面膜的融合的方法。在该系统中实现了类似于20 ms的融合时间。尽管取得了这一进展，但重建系统的一个重要问题是它们在多大程度上模仿了它们应该复制的生理系统。在这项工作中，我们证明，来自大鼠大脑的纯化突触囊泡与含有受体陷阱的平面双层融合的速度与等效的重组囊泡相同，并且二价阳离子可以提高它们的融合效率。钙通过结合一般静电和突触结合蛋白特异性机制促进融合。
Neurotransmitter release at neuronal synapses occurs on a timescale of 1 ms or less. Reconstitution of vesicle fusion from purified synaptic proteins and lipids has played a major role in elucidating the synaptic exocytotic fusion machinery with ever increasing detail. However, one limitation of most reconstitution approaches has been the relatively slow rate of fusion that can be produced in these systems. In a related study, a notable exception is an approach measuring fusion of single reconstituted vesicles bearing the vesicle fusion protein synaptobrevin with supported planar membranes harboring the presynaptic plasma membrane proteins syntaxin and SNAP-25. Fusion times of similar to 20 ms were achieved in this system. Despite this advance, an important question with reconstituted systems is how well they mimic physiological systems they are supposed to reproduce. In this work, we demonstrate that purified synaptic vesicles from rat brain fuse with acceptor-SNARE containing planar bilayers equally fast as equivalent reconstituted vesicles and that their fusion efficiency is increased by divalent cations. Calcium boosts fusion through a combined general electrostatic and synaptotagmin-specific mechanism.