Deciphering the Mechanisms and Cellular Roles of Monomer-Driven Actin Dynamics

项目摘要 为了分裂、移动和交流，细胞依赖于一个动态的肌动蛋白细胞骨架，它可以快速组装和 变化。这是通过将肌动蛋白单体聚合成细丝、构建细丝来实现的 网络，以及将这些网络分解成单体。细胞保持着大量的单体储备 以满足肌动蛋白网络组装的需求。由于它的大小，单体池传统上是 被认为是同质的。然而，我们和其他人最近的工作揭示了不同的亚群 能够以深刻影响细胞行为的方式驱动和修改肌动蛋白动力学的单体。这些 发现告诉我们单体聚合的规则比以前复杂得多。 想着。解决细胞骨架生物学最基本的一个方面的严重知识鸿沟 对于了解肌动蛋白在细胞中的功能至关重要。这也可能最终揭示为什么单体中的缺陷 调节与神经退行性变、炎症性疾病、心脏疾病和癌症有关。 我们目前关于肌动蛋白单体行为的大部分知识来自于溶液生物化学。然而，这些 不同类型的实验不能重现细胞中复杂的单体驱动的肌动蛋白动力学。因此， 我们正在设计将生化原理与细胞成像相结合的策略，以揭示单体肌动蛋白如何 调节活细胞中的细胞骨架。这包括以微摩尔精度控制蛋白质水平，使用 定量图像分析以提取速率常数和浓度，并使用计算模型 以揭示细胞几何形状如何影响肌动蛋白动力学。此外，我们正在开发新的工具来描述 并从超分辨率图像中量化肌动蛋白的超微结构。我们将使用这些创新方法来 解决关于单体驱动的肌动蛋白动力学的以下基本知识空白：1)单体如何 控制复杂肌动蛋白网络的动力学，2)细胞几何形状如何影响单体调节的肌动蛋白 动力学，以及3)单体在调节细胞过程中的新作用。

Project Summary To divide, move, and communicate, cells rely on a dynamic actin cytoskeleton that can rapidly assemble and change. This is achieved by the polymerization of actin monomers into filaments, the construction of filament networks, and the disassembly of these networks back into monomers. Cells maintain a large monomer reserve to meet the demands of actin network assembly. Because of its size, the monomer pool was traditionally considered to be homogeneous. However, recent work by us and others has revealed distinct subgroups of monomers that can drive and modify actin dynamics in ways that profoundly influence cell behavior. These discoveries have shown us that the rules of monomer polymerization are much more complex than previously thought. Addressing this severe knowledge gap in one of the most fundamental aspects of cytoskeletal biology is paramount to understanding how actin functions in cells. It may also finally reveal why defects in monomer regulation are associated with neurodegeneration, inflammatory disorders, cardiac disease and cancer. Most of our current knowledge about actin monomer behavior comes from solution biochemistry. However, these types of experiments cannot reproduce the complex monomer-driven actin dynamics seen in cells. Therefore, we are devising strategies that merge biochemical principles with cellular imaging to reveal how monomeric actin regulates the cytoskeleton in living cells. This includes controlling protein levels with micromolar precision, using quantitative image analysis to extract rate constants and concentrations, and employing computational models to reveal how cellular geometry influences actin dynamics. Additionally, we are developing new tools to describe and quantify actin ultrastructure from super-resolution images. We will use these innovative approaches to address the following fundamental knowledge gaps about monomer-driven actin dynamics: 1) How monomers control the dynamics of complex actin networks, 2) How cell geometry contributes to monomer-regulated actin dynamics, and 3) Novel roles for monomers in the regulation of cellular processes.