Molecular Mechanisms of Exocytotic Proces and Its Regulation

本课题旨在阐明胞吐过程及其调控的分子机制，主要研究结果如下：1）蛋白激酶C（PKC）在囊泡募集和启动过程中的作用：激活的PKC α或PKC 13及其受体分子RACK 1与皮质F-肌动蛋白形成复合物，介导PKC对囊泡启动的促进作用。蛋白激酶C还通过囊泡运动调节囊泡的募集，运动速率为0.03-0.06 μm/s5，囊泡募集的促进作用表现为胞吐事件频率的增加。2）启动的机制和肌动蛋白细胞骨架的作用：抑制肌动蛋白-肌球蛋白相互作用可消除嗜铬颗粒向释放位点的募集，3）SNARE复合物的调节钙调素与VAMP-2的C端结合以及Syntaxin 1A与CaMkinase II的结合调节SNARE复合物的形成，这对胞吐作用是必不可少的。

The aim of this research project is to elucidate the molecular mechanism of exocytotic process and its regulation and we have obtained the following results.1)Roles of PKC in vesicle recruitment and priming.The facilitation of the priming by protein kinase C (PKC) is mediated through the complex between the activated PKC a or PKC 13, their receptor molecule RACK 1 and cortical F-actin. Vesicle recruitment was also regulated by PKC through the vesicle movement at the rate of 0.03-0.06 μm/s5 and the facilitation of vesicle recruitment was detected as an increase in the frequency of exocytotic events.2)The mechanism of priming and roles of actin cytoskeleton.The inhibition of actin-myosin interaction abolished the recruitment of chromaffin granules to the release sites, probably by reducing the population of rapidly moving granules that consist of about 25% of vesicles.3)Regulation of SNARE complex.Binding of calmodulin to C-teminus of VAMP-2, and binding between Syntaxin 1A and CaMkinase II regulate SNARE complex and, are essential for exocytosis.