A PROTEIN ASSEMBLY-DISASSEMBLY PATHWAY IN-VITRO THAT MAY CORRESPOND TO SEQUENTIAL STEPS OF SYNAPTIC VESICLE DOCKING, ACTIVATION, AND FUSION
A PROTEIN ASSEMBLY-DISASSEMBLY PATHWAY IN-VITRO THAT MAY CORRESPOND TO SEQUENTIAL STEPS OF SYNAPTIC VESICLE DOCKING, ACTIVATION, AND FUSION
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DOI：
10.1016/0092-8674(93)90376-2
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发表时间：
1993-11-05
期刊：
影响因子：
64.5
通讯作者：
ROTHMAN, JE
中科院分区：
文献类型：
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作者：
SOLLNER, T;BENNETT, MK;ROTHMAN, JE
SNARE 假说认为，当囊泡上的可溶性 NSF 附着蛋白 (SNAP) 受体 (v-SNARE) 与目标膜上的同源 t-SNARE 配对时，转运囊泡就会选择其融合目标。先前已鉴定出三种突触体膜蛋白：突触蛋白、SNAP-25 (t-SNARE) 和囊泡相关膜蛋白 (VAMP) (v-SNARE)；全部用 SNAP 和 NSF 组装成 20S 融合粒子。我们现在报道，在没有 SNAP 和 NSF 的情况下，这三个 SNARE 形成一个稳定的复合物，也可以结合突触结合蛋白。突触结合蛋白被 α-SNAP 取代，表明这两种蛋白在 SNARE 复合体上共享结合位点，并暗示突触结合蛋白作为“钳子”起作用，以防止在没有信号的情况下进行融合。 α-SNAP-SNARE 复合物可以结合 NSF，并且 NSF 依赖性的 ATP 水解会解离该复合物，从而分离突触蛋白、SNAP-25 和 VAMP。 NSF 的 ATP 水解可能提供启动双层融合的运动。
The SNARE hypothesis holds that a transport vesicle chooses its target for fusion when a soluble NSF attachment protein (SNAP) receptor on the vesicle (v-SNARE) pairs with its cognate t-SNARE at the target membrane. Three synaptosomal membrane proteins have previously been identified: syntaxin, SNAP-25 (t-SNAREs), and vesicle-associated membrane protein (VAMP) (v-SNARE); all assemble with SNAPs and NSF into 20S fusion particles. We now report that in the absence of SNAP and NSF, these three SNAREs form a stable complex that can also bind synaptotagmin. Synaptotagmin is displaced by alpha-SNAP, suggesting that these two proteins share binding sites on the SNARE complex and implying that synaptotagmin operates as a ''clamp'' to prevent fusion from proceeding in the absence of a signal. The alpha-SNAP-SNARE complex can bind NSF, and NSF-dependent hydrolysis of ATP dissociates the complex, separating syntaxin, SNAP-25, and VAMP. ATP hydrolysis by NSF may provide motion to initiate bilayer fusion.