A dynamic template complex mediates Munc18-chaperoned SNARE assembly.
A dynamic template complex mediates Munc18-chaperoned SNARE assembly.
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DOI：
10.1073/pnas.2215124119
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发表时间：
2022-12-06
影响因子：
11.1
通讯作者：
Zhang, Yongli
中科院分区：
文献类型：
--
作者：
Yang, Jie;Jin, Huaizhou;Liu, Yihao;Guo, Yaya;Zhang, Yongli
Munc 18 -1分子伴侣将三种突触SNARE（syntaxin-1、VAMP 2和SNAP-25）折叠和组装成四螺旋束，以介导膜融合和神经递质释放。最近的证据表明，Munc 18 -1，syntaxin-1和VAMP 2首先形成弱模板复合物，然后结合SNAP-25完成SNARE组装。然而，模板复合物的动力学和功能还没有得到很好的理解。使用光镊，我们发现模板复合物经历构象变化，以依赖于突触融合蛋白连接区的方式结合SNAP-25，并且Munc 18在动力学上校正SNARE配对不受其热力学稳定性的影响。我们的研究揭示了一个更动态的模板复合物比在其cryo-EM结构。Munc 18分子伴侣将三个膜锚定的可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）组装成四螺旋束，以介导囊泡和质膜之间的膜融合，导致神经递质或胰岛素释放、葡萄糖转运蛋白（GLUT 4）易位或其他胞吐过程。然而，分子伴侣SNARE组装的分子机制还没有得到很好的理解。最近的证据表明，Munc 18 -1和Munc 18 -3同时结合其同源SNARE以形成三元模板复合物-Munc 18 -1：Syntaxin-1：VAMP 2用于突触囊泡融合，Munc 18 -3：Syntaxin-4：VAMP 2用于GLUT 4易位和胰岛素释放，其促进SNAP-25或SNAP-23的结合以结束SNARE组装。在这里，我们进一步研究的结构，动力学和功能的模板复合物使用光镊。我们的研究结果表明，突触模板复合物以0.054 s-1的速率转换到激活状态，以实现有效的SNAP-25结合。这种转变依赖于突触融合蛋白-1的连接区，其位于螺旋状的形成SNARE基序的上游。此外，模板复合物是稳定的Munc 18 -1中的一个特征不佳的无序环区。虽然突触模板复合物有效地结合SNAP-25和SNAP-23，但GLUT 4模板复合物强烈地偏好SNAP-23而不是SNAP-25，尽管它们组装的SNARE束具有相似的稳定性。总之，我们的数据表明，一个高度动态的模板复合物介导高效和特异性的SNARE组装。
Munc18-1 chaperones coupled folding and assembly of three synaptic SNAREs, syntaxin-1, VAMP2, and SNAP-25, into a four-helix bundle to mediate membrane fusion and neurotransmitter release. Recent evidence suggests that Munc18-1, syntaxin-1, and VAMP2 first form a weak template complex and then bind to SNAP-25 to complete SNARE assembly. However, the dynamics and function of the template complex are not well understood. Using optical tweezers, we found that the template complex undergoes a conformational change to bind SNAP-25 in a way dependent upon the syntaxin linker region and that Munc18 kinetically proofreads SNARE pairing not governed by its thermodynamic stability. Our study reveals a more dynamic template complex than that seen in its cryo-EM structure. Munc18 chaperones assembly of three membrane-anchored soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) into a four-helix bundle to mediate membrane fusion between vesicles and plasma membranes, leading to neurotransmitter or insulin release, glucose transporter (GLUT4) translocation, or other exocytotic processes. Yet, the molecular mechanism underlying chaperoned SNARE assembly is not well understood. Recent evidence suggests that Munc18-1 and Munc18-3 simultaneously bind their cognate SNAREs to form ternary template complexes – Munc18-1:Syntaxin-1:VAMP2 for synaptic vesicle fusion and Munc18-3:Syntaxin-4:VAMP2 for GLUT4 translocation and insulin release, which facilitate the binding of SNAP-25 or SNAP-23 to conclude SNARE assembly. Here, we further investigate the structure, dynamics, and function of the template complexes using optical tweezers. Our results suggest that the synaptic template complex transitions to an activated state with a rate of 0.054 s−1 for efficient SNAP-25 binding. The transition depends upon the linker region of syntaxin-1 upstream of its helical bundle-forming SNARE motif. In addition, the template complex is stabilized by a poorly characterized disordered loop region in Munc18-1. While the synaptic template complex efficiently binds both SNAP-25 and SNAP-23, the GLUT4 template complex strongly favors SNAP-23 over SNAP-25, despite the similar stabilities of their assembled SNARE bundles. Together, our data demonstrate that a highly dynamic template complex mediates efficient and specific SNARE assembly.
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DOI：
10.1126/science.1224492
发表时间：
2012-09-14
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Gao Y;Zorman S;Gundersen G;Xi Z;Ma L;Sirinakis G;Rothman JE;Zhang Y
通讯作者：
Zhang Y
影响因子：
3.4
作者：
Andre, Timon;Classen, Jessica;Soellner, Thomas H.
通讯作者：
Soellner, Thomas H.
影响因子：
5.3
作者：
Delgado-Martinez, Ignacio;Nehring, Ralf B.;Sorensen, Jakob B.
通讯作者：
Sorensen, Jakob B.
影响因子：
7.7
作者：
Choi UB;Zhao M;White KI;Pfuetzner RA;Esquivies L;Zhou Q;Brunger AT
通讯作者：
Brunger AT
Munc18 和 Munc13 在神经递质释放中重要功能的重建
DOI：
10.1126/science.1230473
发表时间：
2013-01-25
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Ma C;Su L;Seven AB;Xu Y;Rizo J
通讯作者：
Rizo J