Rapid bulk endocytosis and its kinetics of fission pore closure at a central synapse
Rapid bulk endocytosis and its kinetics of fission pore closure at a central synapse
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DOI：
10.1073/pnas.0611512104
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发表时间：
2007-06-12
影响因子：
11.1
通讯作者：
Wu, Ling-Gang
中科院分区：
文献类型：
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作者：
Wu, Wei;Wu, Ling-Gang
在胞吐作用后，融合的囊泡必须被回收用于再循环。其中一种回收途径是产生内体样结构，小囊泡从内体样结构中出芽。内体样结构被广泛认为是从质膜缓慢（约1分钟）产生的，这一过程称为大量内吞作用。虽然大量内吞的概念似乎已经确立，但显示突触处大量膜分裂的动力学证据仍然缺失。目前的工作提供了这一缺失的证据在一个萼型突触。我们使用的电容测量技术，它提供了一个高的时间分辨率（约1毫秒），以解决裂变过程。体膜分裂的瞬间反映为约20-500 fF（平均值= 123 fF）的短暂向下电容位移（DCS），10-90%衰减时间约为30-500 ms。至少8.6-11.0%的胞吐囊泡被DCS回收。在DCS期间，检测到裂变孔电导的减小，由此我们发现裂变孔直径以约39 nm/s减小。这提供了在突触的大量内吞作用期间的裂变速率的测量。DCS频率峰值（约为0.021 Hz），
Upon exocytosis, fused vesicles must be retrieved for recycling. One route of retrieval is to generate endosome-like structures, from which small vesicles bud off. Endosome-like structures are widely thought to be generated slowly (approximate to 1 min) from the plasma membrane, a process called bulk endocytosis. Although the concept of bulk endocytosis seems established, the kinetic evidence showing the instant of the bulk membrane fission at synapses is still missing. The present work provides this missing piece of evidence at a calyx-type synapse. We used the capacitance measurement technique, which offers a high time resolution (approximate to 1 ms)to resolve the fission process. The instant of bulk membrane fission was reflected as a brief downward capacitance shift (DCS) of approximate to 20-500 fF (mean = 123 fF) with 10-90% decay time of approximate to 30-500 ms. At least 8.6-11.0% of exocytosed vesicles were retrieved by DCSs. During a DCS, the decrease in the fission pore conductance was detected, from which we found that the fission pore diameter decreased at approximate to 39 nm/s. This provided the measurement of the rate of fission during bulk endocytosis at synapses. The DCS frequency peaked (approximate to 0.021 Hz) in