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

项目概述：网格蛋白介导的内吞作用（CME）是一个重要的途径， 真核生物用于将细胞外货物运输到细胞中。通过控制许多信号 CME是生物体发育的关键组成部分。 虽然网格蛋白包被的囊泡形成的基本机制是已知的，但一个突出的问题是， 问题仍然存在，从早期网格蛋白包被结构到生产性囊泡的转变是如何进行的 控制？生产性囊泡仅在大约一半的时间内从早期结构产生。 建立网格蛋白外套重塑驱动解体或囊泡的机制 形成对于理解货物何时在健康或患病细胞中内化至关重要。的 问题是生物物理建模的自然目标，因为生物体的基本结构 问题（网格蛋白笼）是已知的，但预测货物摄取如何取决于 组分的化学计量、膜弯曲或ATP消耗是非常困难的 因为这个过程的复杂性。我们将实验数据综合成一个全球模型， CME包括交互组件的完整网络，并跟踪空间和时间 每个分子在扩散、反应和聚集时的动力学。与专家小组合作 生物学家，我们的计算模型将提供网格蛋白的定量和可视化记录， 包被囊泡形成。我们建议的工作将确定物理要求， 拆卸膜上的网格蛋白涂层结构，以及膜弯曲的耦合 动态网格蛋白包被的结构组装与不同的衔接蛋白组成。 通过构建一个综合模型的CME组件，我们测试是否 磷酸酶改变网格蛋白包被结构位点处脂质组成的活性可 触发对缺乏货物的站点的选择性拆卸。这项拟议的工作将有助于确定 在快（~ms）或慢（~秒）时间尺度下囊泡形成的物理要求， 不同的细胞类型这项建议的影响将是一个经过验证的“全细胞”型模型， CME和强大的新软件工具，将公开提供共享使用。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， 组装和病毒出芽。

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.