权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Dynamic behavior of the proteins involved in the synaptic vesicle cycle

参与突触小泡循环的蛋白质的动态行为

基本信息

批准号：
16500238
负责人：
ABE Teruo
金额：
$ 2.3万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16500238/
关键词：
SNAREs Neurotransmitter release Drosophila Synaphin complexin Synaptic vesicle シナプス小脳

项目摘要

When an action potential reaches the nerve terminal, Ca^<2+>-influx through open voltage-sensitive Ca channels triggers the exocytosis of synaptic vesicles, thereby releasing neurotransmitter molecules. Recent studies indicate that synaptic SNARE proteins (syntaxin, SNAP-25 and VAMP/synaptobrevin) are the minimal machinery for the synaptic vesicle fusion with the presynaptic membrane. Cytosolic proteins including NSF,SNAPs,nSec1/Munc18-1 and synaphin/complexin regulate the fusion. We have used the neuromuscular junction of Drosophila larvae to examine the localization of these proteins involved in the synaptic vesicle cycle and its regulation. Localization of these proteins was determined by immunofluorescence after fixation. In resting conditions, syntaxin was distributed along the internal surface of the nerve terminal with some densely stained regions. Synaphin localization was very similar to that of syntaxin. After exocytosis induced by high K^+-treatment, syntaxin localization did not significantly differ from the resting state. However, synaphin distribution became diffuse over the cytoplasm, suggesting its dynamic movement during or after exocytosis. Sibire^<ts> mutant also showed the dynamic movement of synaphin at a restrictive temperature where endocytosis of synaptic vesicles was completely suppressed without affecting exocytosis. Thus the dynamic movement of synaphin is related to synaptic vesicle exocytosis but not to endocytosis. The movement was blocked by the casein kinase II (CKII) inhibitors (5,6-dichlorobenzimidazole riboside and 4,5,6,7-tetrabromotriazole) but not by inhibitors for Ca^<2+>/CaM kinase II, A-kinase or C-kinase, suggesting the involvement of protein phosphorylation by CKII in the movement of synaphin.

当动作电位到达神经末梢时，通过开放的电压敏感钙通道的钙离子内流触发突触小泡的胞吐，从而释放神经递质分子。最近的研究表明，突触SNARE蛋白(Synsorin、SNAP-25和VAMP/synaptobrevin)是突触小泡与突触前膜融合的最小机制。胞浆蛋白包括NSF、SNAPS、nSec1/Munc18-1和Synphin/Complin调节融合。我们利用果蝇幼虫的神经肌肉接头来研究这些与突触小泡周期有关的蛋白质的定位及其调控。固定后用免疫荧光法测定这些蛋白的定位。静息状态下，突触素沿神经末梢内表面分布，有一些浓染的区域。突触素的定位与合成素的定位非常相似。在高K~(++)处理诱导胞吐后，突触素的定位与静息状态无显著差异。然而，突触素的分布弥漫在细胞质中，表明其在胞吐过程中或胞吐后的动态运动。突变体Sibire^&lt；ts&gt；在有限的温度下也表现出突触蛋白的动态运动，突触小泡的内吞作用完全被抑制，而不影响胞吐作用。因此，突触素的动态运动与突触小泡的胞吐作用有关，而与内吞作用无关。酪蛋白激酶II(CKII)抑制剂(5，6-二氯苯并咪唑核苷和4，5，6，7-四溴三氮唑)可阻断突触素的运动，但不能被钙/钙调素激酶II、A-激酶或C-激酶的抑制剂阻断，提示CKII参与了突触素的运动过程。