The precise cell-to-cell communication relies on SNARE-catalyzed membrane fusion. Among ∼70 copies of synaptobrevin2 (syb2) in synaptic vesicles, only ∼3 copies are sufficient to facilitate the fusion process at the presynaptic terminal. It is unclear what dictates the number of SNARE complexes that constitute the fusion pore assembly. The structure-function relation of these dynamic pores is also unknown. Here, we demonstrate that syb2 monomers and dimers differentially engage in regulating the trans-SNARE assembly during membrane fusion. The differential recruitment of two syb2 structures at the membrane fusion site has consequences in regulating individual nascent fusion pore properties. We have identified a few syb2 transmembrane domain residues that control monomer/dimer conversion. Overall, our study indicates that syb2 monomers and dimers are differentially recruited at the release sites for regulating membrane fusion events.

中文翻译：

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Synaptobrevin2 单体和二聚体以不同方式参与调节功能性反式 SNARE 组装。

精确的细胞间通讯依赖于 SNARE 催化的膜融合。在突触小泡中约 70 个 synaptobrevin2 (syb2) 拷贝中，只有约 3 个拷贝足以促进突触前末端的融合过程。目前还不清楚是什么决定了构成融合孔组件的 SNARE 复合体的数量。这些动态孔隙的结构-功能关系也是未知的。在这里，我们证明 syb2 单体和二聚体在膜融合过程中差异性地参与调节 trans-SNARE 组装。膜融合位点两个 syb2 结构的差异招募对调节个体新生融合孔特性产生影响。我们已经鉴定了一些控制单体/二聚体转换的 syb2 跨膜结构域残基。总体而言，我们的研究表明，syb2 单体和二聚体在释放位点上有差异地招募来调节膜融合事件。