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Modeling SNARE-Mediated Membrane Fusion

SNARE 介导的膜融合建模

基本信息

批准号：
10614046
负责人：
Ben O'Shaughnessy
金额：
$ 34.02万
依托单位：
COLUMBIA UNIV NEW YORK MORNINGSIDE
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10614046
关键词：
Action Potentials Beta Cell Biochemical Catalogs Cell fusion Cell membrane Cells Central Nervous System Chromaffin Cells Closure by clamp Communities Complex Computer Models Core Protein Coupled Data Dense Core Vesicle Docking Dynamin Event Evoked Potentials Evolution Exocytosis Family Functional disorder Funding Goals Grain Growth Hormones Hot Spot Impairment Informal Social Control Kinetics Laboratories Machine Learning Measurement Mechanics Mediating Membrane Membrane Fusion Membrane Lipids Modeling Molecular Mutate Mutation Neurodegenerative Disorders Neurodevelopmental Disorder Neuroendocrine Cell Neurons Neurotransmitters Pathway interactions Physiological Probability Process Property Proteins Regulation of Exocytosis Reproducibility Research Respiratory Diaphragm Rest Rotation Running SNAP receptor Scheme Secretory Vesicles Shapes Signal Transduction Site Stimulus Structure Study models Synapses Synaptic Cleft Synaptic Vesicles Testing Thinness Type 2 diabetic Vesicle experimental study foot hydrophilicity in silico insulin secretion mathematical model millisecond model building molecular dynamics multi-scale modeling nanodisk neurotransmission neurotransmitter release novel postsynaptic predictive modeling reconstitution response sensor simulation synaptotagmin syntaxin target SNARE proteins vesicular SNARE proteins vesicular release

项目摘要

PROJECT SUMMARY Many basic processes rely on secretion of bioactive molecules by exocytosis, when membrane-enclosed vesicles containing neurotransmitters (NTs), hormones or other molecules fuse with the plasma membrane (PM) and release their contents through fusion pores. Neurotransmission relies on NT release at neuronal synapses, when a multicomponent machinery senses Ca!"influx triggered by an action potential and fuses small synaptic vesicles with the plasma membrane on sub-millisecond timescales, releasing NTs into the synaptic cleft to elicit a post-synaptic response. Other regulated exocytosis is slower, such as hormone release from neuroendocrine cells when a stimulus provokes large dense core vesicles to release contents after seconds or longer. In all cases, the membrane fusion step is accomplished by the SNARE proteins, when vesicle-associated VAMP (the v-SNARE) and two PM-associated t-SNAREs syntaxin and SNAP 25 zipper into a ternary complex, pulling the membranes together and fusing them. However, the mechanism of membrane fusion remains unclear. Other components in the machinery block (“clamp”) SNARE-mediated fusion, until the Ca!"signal releases the clamp. Synaptotagmin (Syt) is the Ca!"sensor for synchronous release, but the molecular identity of the clamp and the Ca!"-triggered unclamping mechanism are not established. Mutations in SNARE proteins and other NT release machinery components are associated with neurodevelopmental and neurodegenerative disorders, and impaired fusion pore dilation is associated with reduced insulin secretion by β-cells of type-2 diabetics. The proposed research aims to use mathematical modeling to establish the mechanisms of regulated membrane fusion and the mechanisms that regulate the vesicle and its pore for controlled contents release following fusion. From the previous funding period, we have working molecular dynamics (MD) simulations of SNARE-mediated membrane fusion and of the NT release machinery incorporating the core SNARE and Syt components. The simulations used sufficiently coarse-grained (CG) representations to achieve the computationally demanding millisecond physiological timescales of fusion and release. Aim 1 is to advance the SNARE-mediated fusion simulations with more realistic SNAREs, and to use machine learning to catalogue the pathways to membrane fusion as a function of the size of the fusing vesicles and other key variables. Mutated SNAREs will be simulated and compared to experiments by collaborators. Aim 2 is to use continuum mathematical modeling to establish the structure, energetics and evolution of the fused vesicle-PM complex and its fusion pore, and the mechanisms of SNARE- and Syt-mediated pore dilation. Aim 3 is to advance the MD simulations of the NT release machinery by introducing molecularly explicit representation of the membranes, and by incorporating additional components as their interactions become experimentally characterized, toward a long-term goal of “reconstituting” the machinery in silico. Simulations will test hypothesized Ca!"-triggered unclamping schemes, and will be run with mutations in the SNARE and Syt components that will be implemented experimentally by our collaborators.

项目摘要许多基本过程依赖于当膜封闭时通过胞吐分泌生物活性分子。含有神经递质（NT）、激素或其他分子的囊泡与质膜（PM）融合并通过融合孔释放它们的内容物。神经传递依赖于神经元突触处的NT释放，当一个多组件机器感知到Ca！“由动作电位触发的电流流入，囊泡与质膜在亚毫秒的时间尺度上，释放NT到突触间隙中，突触后反应其他受调节的胞吐作用较慢，如神经内分泌的激素释放，当刺激物刺激大而致密的核心囊泡在数秒或更长时间后释放内容物时，细胞会发生反应。在所有情况下，当囊泡相关的VAMP (the v-SNARE）和两个PM相关的t-SNARE突触融合蛋白和SNAP 25拉链成三元复合物，将细胞膜融合在一起然而，膜融合的机制仍不清楚。其他在机械块（“钳”）SNARE介导的融合，直到Ca！“信号释放夹钳。 Synaptotagmin（Syt）是Ca！“传感器同步释放，但分子身份的钳和卡！“-触发松开机构未建立。SNARE蛋白突变和其他NT释放机械组件与神经发育和神经退行性疾病有关，受损的融合孔扩张与2型糖尿病患者的β细胞的胰岛素分泌减少有关。这项研究的目的是利用数学模型来建立调节膜的机制融合和调节囊泡及其孔以控制融合后内容物释放的机制。从上一个资助期，我们有工作的分子动力学（MD）模拟SNARE介导的膜融合和NT释放机制，包括核心SNARE和Syt组件。的模拟使用足够粗粒度（CG）表示，以实现计算要求高的毫秒级的融合和释放生理时间尺度。目的1是研究SNARE介导的融合用更真实的SNARE模拟，并使用机器学习来编目膜的途径，融合作为融合囊泡的大小和其他关键变量的函数。将模拟突变的SNARE 并与合作者的实验进行比较。目的二是利用连续介质数学模型建立融合囊泡-PM复合物及其融合孔的结构、能量学、演化及其机理 SNARE和Syt介导的毛孔扩张。目的3是推进NT释放机制的MD模拟通过引入膜的分子显式表示，并通过引入额外的组分，随着它们的相互作用变得实验特征化，朝着“重建” 机器在silico。模拟将测试假设的Ca！“-触发的松开方案，并将使用 SNARE和Syt组件中的突变，将由我们的合作者进行实验。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Host Cell Membrane Capture by the SARS-CoV-2 Spike Protein Fusion Intermediate.

DOI：
10.1021/acscentsci.3c00158
发表时间：
2023-06-28
期刊：
ACS CENTRAL SCIENCE
影响因子：
18.2
作者：
Su, Rui;Zeng, Jin;Marcink, Tara C.;Porotto, Matteo;Moscona, Anne;O'Shaughnessy, Ben
通讯作者：
O'Shaughnessy, Ben

SNARE-mediated membrane fusion is a two-stage process driven by entropic forces.

SNARE 介导的膜融合是由熵力驱动的两阶段过程。