Vesicular restriction of synaptobrevin suggests a role for calcium in membrane fusion

被引：148

作者：

Hu, K ^{[1
]}

Carroll, J ^{[1
]}

Fedorovich, S ^{[1
]}

Rickman, C ^{[1
]}

Sukhodub, A ^{[1
]}

Davletov, B ^{[1
]}

机构：

[1] MRC, Mol Biol Lab, Cambridge CB2 2QH, England

来源：

NATURE | 2002年 / 415卷 / 6872期

关键词：

D O I：

10.1038/415646a

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Release of neurotransmitter occurs when synaptic vesicles fuse with the plasma membrane. This neuronal exocytosis is triggered by calcium and requires three SNARE (soluble-N-ethylmaleimide-sensitive factor attachment protein receptors) proteins: synaptobrevin (also known as VAMP) on the synaptic vesicle, and syntaxin and SNAP-25 on the plasma membrane(1-4). Neuronal SNARE proteins form a parallel four-helix bundle that is thought to drive the fusion of opposing membranes(5,6). As formation of this SNARE complex in solution does not require calcium, it is not clear what function calcium has in triggering SNARE-mediated membrane fusion. We now demonstrate that whereas syntaxin and SNAP-25 in target membranes are freely available for SNARE complex formation, availability of synaptobrevin on synaptic vesicles is very limited. Calcium at micromolar concentrations triggers SNARE complex formation and fusion between synaptic vesicles and reconstituted target membranes. Although calcium does promote interaction of SNARE proteins between opposing membranes, it does not act by releasing synaptobrevin from synaptic vesicle restriction. Rather, our data suggest a mechanism in which calcium-triggered membrane apposition enables syntaxin and SNAP-25 to engage synaptobrevin, leading to membrane fusion.

引用

页码：646 / 650

页数：5

共 30 条

[1] Membrane-embedded synaptotagmin penetrates cis or trans target membranes and clusters via a novel mechanism [J].