Vesicular Sterols Are Essential for Synaptic Vesicle Cycling
Vesicular Sterols Are Essential for Synaptic Vesicle Cycling
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DOI：
10.1523/jneurosci.4132-10.2010
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发表时间：
2010-11-24
影响因子：
5.3
通讯作者：
Charlton, Milton P.
中科院分区：
文献类型：
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作者：
Dason, Jeffrey S.;Smith, Alex J.;Charlton, Milton P.
突触小泡具有较高的甾醇含量，但小泡甾醇在囊泡回收过程中的重要性尚不清楚。我们使用果蝇温度敏感的动力突变体 shibire-ts1 来阻断回收突触小泡的内吞作用，并将它们可逆地捕获在质膜上，在那里它们可以被甾醇提取。去除内吞阻滞后，捕获的囊泡中甾醇的耗尽阻止了突触传递的恢复。使用突触 Hluorin、FM1-43 和 FM4-64 对囊泡回收进行的测量表明，囊泡甾醇耗尽后膜修复受损。当在囊泡捕获之前提取质膜甾醇时，没有观察到囊泡回收缺陷。超微结构分析表明内体的积累和突触末梢中突触小泡形成的缺陷，导致囊泡甾醇耗尽。我们的结果证明了高囊泡甾醇浓度对于内吞作用的重要性，并表明囊泡和膜甾醇池在囊泡回收过程中不易混合。
Synaptic vesicles have a high sterol content, but the importance of vesicular sterols during vesicle recycling is unclear. We used the Drosophila temperature-sensitive dynamin mutant, shibire-ts1, to block endocytosis of recycling synaptic vesicles and to trap them reversibly at the plasma membrane where they were accessible to sterol extraction. Depletion of sterols from trapped vesicles prevented recovery of synaptic transmission after removal of the endocytic block. Measurement of vesicle recycling with synaptop Hluorin, FM1-43, and FM4-64 demonstrated impaired membrane retrieval after vesicular sterol depletion. When plasma membrane sterols were extracted before vesicle trapping, no vesicle recycling defects were observed. Ultrastructural analysis indicated accumulation of endosomes and a defect in the formation of synaptic vesicles in synaptic terminals subjected to vesicular sterol depletion. Our results demonstrate the importance of a high vesicular sterol concentration for endocytosis and suggest that vesicular and membrane sterol pools do not readily intermingle during vesicle recycling.