Mechanisms of Protein Self-Assembly Coupled to Membrane Mechanics in the Cell.

项目摘要：网状蛋白介导的内吞作用(CME)是ALL使用的一种基本途径 真核生物将胞外货物运输到细胞内。通过控制许多信号 CME在细胞间传播，是生物体发育的关键组成部分。 尽管已知笼蛋白包膜囊泡形成的基本机制，但一个突出的 问题仍然存在，从早期的网状蛋白涂层结构到产生囊泡的过渡是如何进行的？ 控制？只有大约一半的时间是从早期结构产生产生的囊泡。 建立笼状蛋白被膜重塑可以驱动分解或囊泡的机制 对于理解货物何时内化在健康或患病的细胞中，形成是至关重要的。这个 问题是生物物理建模的自然目标，因为 问题(笼子)是已知的，但预测货物吸收如何取决于 化学计量的成分，膜弯曲，或三磷酸腺苷支出是非常困难的 因为这个过程很复杂。我们将实验数据合成到一个全球模型中 包括交互组件的完整网络并跟踪空间和时间的CME 每个分子在扩散、反应和组装时的动力学。与专家小组合作 生物学家们，我们的计算模型将提供笼络蛋白的定量和可视记录- 包被的囊泡形成。我们提议的工作将确定以下物理要求 膜上网状蛋白涂层结构的拆解和膜弯曲的耦合 具有不同接头蛋白组成的笼状蛋白涂层结构组件的动力学。 通过构建CME组件的综合模型，我们检验了CME组件是否 磷酸酶在改变包被蛋白结构部位的脂质成分中的活性可以 触发对缺乏货物的地点的选择性拆卸。这项拟议的工作将有助于确定 在快(~毫秒)或慢(~秒)时间刻度下形成囊泡的物理要求，单位 不同的细胞类型。这项提议的影响将是一个经过验证的全细胞类型的模型 CME和强大的新软件工具，将公开提供给共享使用。该软件 将适用于研究多蛋白组装和膜重塑的机制 不仅在CME中，而且在广泛的细胞过程中，包括细胞分裂、细胞骨架 组装和病毒萌芽。

Project Summary: Clathrin-mediated endocytosis (CME) is an essential pathway used by all eukaryotes for the transport of extracellular cargo into the cell. By controlling many of the signals that are transmitted between cells, CME is a key component in the development of organisms. Although the basic mechanism of clathrin-coated vesicle formation is known, an outstanding question remains, how is the transition from early clathrin coated structures to productive vesicles controlled? Productive vesicles are only produced from early structures about half of the time. Establishing the mechanisms whereby clathrin-coat remodeling can drive disassembly or vesicle formation is critical to understanding when cargo is internalized in healthy or diseased cells. The problem is a natural target for biophysical modeling because the fundamental structure of the problem (the clathrin cage) is known, but predicting how cargo uptake depends on the stoichiometry of the components, membrane bending, or ATP-expenditure is remarkably difficult because of the complexity of the process. We synthesize experimental data into a global model of CME that includes the full network of interacting components and tracks the spatial and temporal dynamics of each molecule as they diffuse, react, and assemble. In collaboration with expert cell biologists, our computational model will provide a quantitative and visual record of clathrin- coated vesicle formation. Our proposed work will determine physical requirements for disassembling clathrin-coated structures on membranes, and the coupling of membrane bending dynamics to clathrin-coated structure assembly with varying adaptor protein composition. Through construction of a comprehensive model of CME components, we test whether the activity of phosphatases in altering lipid composition at sites of clathrin-coated structures can trigger selective disassembly of sites lacking cargo. This proposed work will help determine the physical requirements for vesicle formation at fast (~ms) or slow (~seconds) time-scales, in distinct cell types. The impact of this proposal will be a validated, `whole-cell' type model of CME and powerful new software tools that will be publicly available for shared use. The software will be applicable to studying mechanisms of mutli-protein assembly and membrane remodeling not only in CME, but a wide range of cellular processes including cell division, cytoskeletal assembly, and viral budding.