Diacylglycerol-dependent hexamers of the SNARE-assembling chaperone Munc13-1 cooperatively bind vesicles.
Diacylglycerol-dependent hexamers of the SNARE-assembling chaperone Munc13-1 cooperatively bind vesicles.
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DOI：
10.1073/pnas.2306086120
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发表时间：
2023-10-31
影响因子：
11.1
通讯作者：
Rothman, James E.
中科院分区：
文献类型：
--
作者：
Li, Feng;Grushin, Kirill;Coleman, Jeff;Pincet, Frederic;Rothman, James E.
Munc13-1是一种分子伴侣子，促进突触活跃区突触囊泡的招募和对接。通过模型膜和统计建模，我们发现Munc13-1主要在脂质膜上富含二酰基甘油的微结构域上形成六聚体。这些六聚体协同作用，从溶液中捕获囊泡。统计数据表明，每个六聚体与一个囊泡结合。基于晶体学数据的点突变破坏了Munc13-1六方界面上的相互作用，改变了其寡聚化状态，不再观察到六聚体。此外，突变寡聚物失去了结合囊泡的协同性。我们的研究表明，在脂质双层上观察到的Munc13-1六聚体类似于晶体学显示的六边形。Munc13-1对于突触活跃区的囊泡对接和融合至关重要。在这里，我们报告了Munc13-1在磷脂双层中富含二酰基甘油的微域内自组装成分子簇。尽管这些簇中Munc13-1分子的拷贝数分布广泛，但系统的泊松分析表明，这很可能是两种分子物种的结果：单体和主要是六聚体低聚物。每个低聚物能够独立地捕获一个囊泡。在对立磷脂双层之间形成的Munc13-1晶体中也观察到六聚体[K]。格鲁申，R. V. Kalyana Sundaram， C. V. Sindelar， J. E. Rothman, Proc. Natl。学会科学。[j].美国科学学报（自然科学版）119,e2121259119（2022）。针对稳定六边形晶体的触点的突变也破坏了孤立的六聚体，表明它们是相同的。此外，这些突变还将囊泡结合从合作模式转变为渐进模式。我们的研究提供了一种独立的方法，表明Munc13-1主要可以在脂质双分子层上形成六聚体，每一层都能够捕获囊泡。
Munc13-1 is a molecular chaperon that facilitates recruitment and docking of synaptic vesicles at the active zone of the synapse. Using model membranes and statistical modeling, we show that Munc13-1 forms mainly hexamers on diacylglycerol rich microdomains on lipid membranes. These hexamers act cooperatively to capture vesicles from a solution. Statistics show that each hexamer binds to one vesicle. Disruption of the interactions at Munc13-1 hexagonal interface by point mutations based on crystallographic data alters its oligomerization state and hexamers are no longer observed. Furthermore, the mutant oligomer loses its cooperativity in binding vesicles. Our study suggests that the Munc13-1 hexamers observed on lipid bilayers resemble the hexagons revealed by crystallography. Munc13-1 is essential for vesicle docking and fusion at the active zone of synapses. Here, we report that Munc13-1 self-assembles into molecular clusters within diacylglycerol-rich microdomains present in phospholipid bilayers. Although the copy number of Munc13-1 molecules in these clusters has a broad distribution, a systematic Poisson analysis shows that this is most likely the result of two molecular species: monomers and mainly hexameric oligomers. Each oligomer is able to capture one vesicle independently. Hexamers have also been observed in crystals of Munc13-1 that form between opposed phospholipid bilayers [K. Grushin, R. V. Kalyana Sundaram, C. V. Sindelar, J. E. Rothman, Proc. Natl. Acad. Sci. U.S.A. 119, e2121259119 (2022)]. Mutations targeting the contacts stabilizing the crystallographic hexagons also disrupt the isolated hexamers, suggesting they are identical. Additionally, these mutations also convert vesicle binding from a cooperative to progressive mode. Our study provides an independent approach showing that Munc13-1 can form mainly hexamers on lipid bilayers each capable of vesicle capture.
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影响因子：
5
作者：
通讯作者：
--
影响因子：
16.2
作者：
Lai Y;Choi UB;Leitz J;Rhee HJ;Lee C;Altas B;Zhao M;Pfuetzner RA;Wang AL;Brose N;Rhee J;Brunger AT
通讯作者：
Brunger AT
影响因子：
3.5
作者：
Li, Xia;Radhakrishnan, Abhijith;Rothman, James E.
通讯作者：
Rothman, James E.
DOI：
10.1073/pnas.2121259119
发表时间：
2022-02-15
影响因子：
11.1
作者：
Grushin K;Kalyana Sundaram RV;Sindelar CV;Rothman JE
通讯作者：
Rothman JE
影响因子：
16.6
作者：
Camacho M;Basu J;Trimbuch T;Chang S;Pulido-Lozano C;Chang SS;Duluvova I;Abo-Rady M;Rizo J;Rosenmund C
通讯作者：
Rosenmund C