Direct imaging of rapid tethering of synaptic vesicles accompanying exocytosis at a fast central synapse
Direct imaging of rapid tethering of synaptic vesicles accompanying exocytosis at a fast central synapse
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DOI：
10.1073/pnas.2000265117
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发表时间：
2020-06-23
影响因子：
11.1
通讯作者：
Sakaba, Takeshi
中科院分区：
文献类型：
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作者：
Miki, Takafumi;Midorikawa, Mitsuharu;Sakaba, Takeshi
小脑苔藓纤维末梢需要高速率的突触囊泡（SV）释放以进行快速信息处理。由于释放位点的数量有限，快速SV重新加载对于实现持续释放是必要的。然而，尚未直接观察到快速重新加载。在这里，我们用全内反射荧光（TIRF）显微镜观察突触前膜附近SV的运动。刺激后，SV出现在TIRF场中，并以出乎意料的快速时间过程束缚在突触前膜上，几乎与SV因释放而消失一样快。然而，这种刺激诱导的束缚被抑制胞吐作用所消除，表明束缚与先前的胞吐作用紧密耦合。新拴系的囊泡成为融合能力，而不是立即，但只有300毫秒至400毫秒后拴系。结合模型模拟，我们提出，快速拴系导致立即填补空出的空间和释放网站内
A high rate of synaptic vesicle (SV) release is required at cerebellar mossy fiber terminals for rapid information processing. As the number of release sites is limited, fast SV reloading is necessary to achieve sustained release. However, rapid reloading has not been observed directly. Here, we visualize SV movements near presynaptic membrane using total internal reflection fluorescence (TIRF) micros- copy. Upon stimulation, SVs appeared in the TIRF-field and became tethered to the presynaptic membrane with unexpectedly rapid time course, almost as fast as SVs disappeared due to release. However, such stimulus -induced tethering was abolished by inhibiting exocyto- sis, suggesting that the tethering is tightly coupled to preceding exo- cytosis. The newly tethered vesicles became fusion competent not immediately but only 300 ms to 400 ms after tethering. Together with model simulations, we propose that rapid tethering leads to an im- mediate filling of vacated spaces and release sites within