Ca2+-synaptotagmin directly regulates t-SNARE function during reconstituted membrane fusion
Ca2+-synaptotagmin directly regulates t-SNARE function during reconstituted membrane fusion
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DOI：
10.1038/nsmb1076
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发表时间：
2006-04-01
影响因子：
16.8
通讯作者：
Chapman, ER
中科院分区：
文献类型：
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作者：
Bhalla, A;Chicka, MC;Chapman, ER
在神经末梢，胞外分泌由SNARE蛋白介导，并受Ca2+和synaptotagmin-1 （syt）调节。Ca2+促进syt与阴离子磷脂和靶膜SNAREs (t-SNAREs) SNAP-25和syntaxin的相互作用。在这里，我们通过比较Ca2+-syt对神经元（SNAP-25， syntaxin和synaptobrevin）和酵母（Sso1p， Sec9c和Snc2p） SNAREs的影响，使用定义的重构融合实验来直接确定syt-t-SNARE相互作用是否将Ca2+耦合到膜融合。通过与阴离子磷脂的相互作用，Ca2+-syt聚集神经元和酵母SNARE脂质体达到相似的程度。然而，Ca2+-syt仅能结合和刺激神经元SNAREs介导的融合，而对酵母SNAREs没有影响。因此，Ca2+-syt通过与t-SNAREs的直接相互作用来调节融合，而不仅仅是通过囊泡的聚集。Ca2+-syt驱动SNAP-25组装到膜嵌入的syntaxin上，提供了Ca2+-syt改变t-SNARE结构的直接证据。
In nerve terminals, exocytosis is mediated by SNARE proteins and regulated by Ca2+ and synaptotagmin-1 ( syt). Ca2+ promotes the interaction of syt with anionic phospholipids and the target membrane SNAREs ( t-SNAREs) SNAP-25 and syntaxin. Here, we have used a defined reconstituted fusion assay to determine directly whether syt-t-SNARE interactions couple Ca2+ to membrane fusion by comparing the effects of Ca2+-syt on neuronal ( SNAP-25, syntaxin and synaptobrevin) and yeast ( Sso1p, Sec9c and Snc2p) SNAREs. Ca2+-syt aggregated neuronal and yeast SNARE liposomes to similar extents via interactions with anionic phospholipids. However, Ca2+-syt was able to bind and stimulate fusion mediated by only neuronal SNAREs and had no effect on yeast SNAREs. Thus, Ca2+-syt regulates fusion through direct interactions with t-SNAREs and not solely through aggregation of vesicles. Ca2+-syt drove assembly of SNAP-25 onto membrane-embedded syntaxin, providing direct evidence that Ca2+-syt alters t-SNARE structure.