Structural characterization of the Rabphilin-3A-SNAP25 interaction
Structural characterization of the Rabphilin-3A-SNAP25 interaction
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DOI：
10.1073/pnas.1702542114
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发表时间：
2017-07-03
影响因子：
11.1
通讯作者：
Verdaguer, Nuria
中科院分区：
文献类型：
--
作者：
Ferrer-Orta, Cristina;Perez-Sanchez, Maria Dolores;Verdaguer, Nuria
膜融合在真核细胞的许多生物学过程中是必不可少的，包括突触传递。Rabphilin-3A是一种膜运输蛋白，参与神经元和神经内分泌细胞中分泌囊泡胞吐的钙依赖性调节，但其潜在机制仍知之甚少。在这里，我们报告Rabphilin-3A C2B-SNAP 25和C2B-磷脂酰肌醇4，5-二磷酸（PIP 2）复合物的晶体结构和生化分析，揭示Rabphilin-3A C2结构域如何与PIP 2/Ca 2+和SNAP 25合作结合质膜，采用与完整的SNARE复合物相互作用相容的构象。与synaptotagmin 1-SNARE的比较表明，两种蛋白质接触相同的SNAP 25表面，但Rabphilin-3A使用独特的结构元件。在这里获得的数据表明，一个模型来解释的Ca 2+依赖的融合过程，膜弯曲与无数的变化取决于C2结构域轴承蛋白质的性质，发光理解微调控制不同的囊泡融合事件。
Membrane fusion is essential in a myriad of eukaryotic cell biological processes, including the synaptic transmission. Rabphilin-3A is a membrane trafficking protein involved in the calcium-dependent regulation of secretory vesicle exocytosis in neurons and neuroendocrine cells, but the underlying mechanism remains poorly understood. Here, we report the crystal structures and biochemical analyses of Rabphilin-3A C2B-SNAP25 and C2B-phosphatidylinositol 4,5-bisphosphate (PIP2) complexes, revealing how Rabphilin-3A C2 domains operate in cooperation with PIP2/Ca2+ and SNAP25 to bind the plasma membrane, adopting a conformation compatible to interact with the complete SNARE complex. Comparisons with the synaptotagmin 1-SNARE show that both proteins contact the same SNAP25 surface, but Rabphilin-3A uses a unique structural element. Data obtained here suggest a model to explain the Ca2+-dependent fusion process by membrane bending with a myriad of variations depending on the properties of the C2 domain-bearing protein, shedding light to understand the fine-tuning control of the different vesicle fusion events.