Abstract:
Neurotransmitter in vesicles is released through a fusion pore when vesicles fuse with the plasma membrane. Subsequent retrieval of the fused vesicle membrane is the key step in recycling exocytosed vesicles. Application of advanced electrophysiological techniques to a large nerve terminal, the calyx of Held, has led to recordings of endocytosis, individual vesicle fusion and retrieval, and the kinetics of the fusion pore opening process and the fission pore closure process. These studies have revealed three kinetically different forms of endocytosis-rapid, slow, and bulk-and two forms of fusion-full collapse and kiss-and-run. Calcium influx triggers all kinetically distinguishable forms of endocytosis at calyces by activation of calmodulin/calcineurin signaling pathway and protein kinase C, which may dephosphorylate and phosphorylate endocytic proteins. Polymerized actin may provide mechanical forces to bend the membrane, forming membrane pits, the precursor for generating vesicles. These research advancements are reviewed in this chapter.
摘要:
当囊泡与质膜融合时,囊泡中的神经递质通过融合孔释放。随后回收融合的囊泡膜是回收胞外囊泡的关键步骤。将先进的电生理技术应用于大型神经末梢,Held的花萼,导致内吞的记录,个体囊泡融合和取回,以及聚变孔开放过程和裂变孔闭合过程的动力学。这些研究揭示了三种动力学上不同形式的内吞作用-快速,慢,和散装-和两种形式的融合-完全崩溃和亲吻和奔跑。钙内流通过激活钙调蛋白/钙调磷酸酶信号通路和蛋白激酶C触发所有动力学上可区分的胞吞形式。这可能去磷酸化和磷酸化内吞蛋白。聚合肌动蛋白可以提供机械力来弯曲膜,形成膜坑,产生囊泡的前体。本章对这些研究进展进行了综述。