School of Life Science and Biotechnology and Center for Human Interface Nanotechnology, Sungkyunkwan University, Suwon 440-746, South Korea.
Proc Natl Acad Sci U S A. 2010 Dec 21;107(51):22145-50. doi: 10.1073/pnas.1006899108. Epub 2010 Dec 6.
Neuronal SNARE proteins mediate neurotransmitter release at the synapse by facilitating the fusion of vesicles to the presynaptic plasma membrane. Cognate v-SNAREs and t-SNAREs from the vesicle and the plasma membrane, respectively, zip up and bring about the apposition of two membranes attached at the C-terminal ends. Here, we demonstrate that SNARE zippering can be modulated in the midways by wedging with small hydrophobic molecules. Myricetin, which intercalated into the hydrophobic inner core near the middle of the SNARE complex, stopped SNARE zippering in motion and accumulated the trans-complex, where the N-terminal region of v-SNARE VAMP2 is in the coiled coil with the frayed C-terminal region. Delphinidin and cyanidin inhibited N-terminal nucleation of SNARE zippering. Neuronal SNARE complex in PC12 cells showed the same pattern of vulnerability to small hydrophobic molecules. We propose that the half-zipped trans-SNARE complex is a crucial intermediate waiting for a calcium trigger that leads to fusion pore opening.
神经元 SNARE 蛋白通过促进囊泡与突触前质膜融合来介导神经递质的释放。囊泡和质膜上的同源 v-SNARE 和 t-SNARE 分别在 C 末端 zipper 并使附着在两端的两个膜接近。在这里，我们证明 SNARE zipper 可以通过小分子楔入在中间阶段进行调节。杨梅素插入到 SNARE 复合物中间附近的疏水性内部核心，阻止 SNARE zipper 运动并积累反式复合物，其中 v-SNARE VAMP2 的 N 末端区域与展开的 C 末端区域形成卷曲螺旋。飞燕草素和矢车菊素抑制 SNARE zipper 的 N 末端成核。PC12 细胞中的神经元 SNARE 复合物对小分子疏水性物质表现出相同的脆弱性模式。我们提出，半 zipped 反式 SNARE 复合物是一个关键的中间等待钙离子触发导致融合孔打开。
