Unravelling Mechanisms of Endosomal Signaling with Designer Nanomaterials

摘要 内体，活细胞内的膜隔室，越来越多地被认为是离散的“枢纽”， 在空间和时间上调节细胞信号通路的网络。物理现象，如 核内体膜上的蛋白质和核内体的主动转运被假设起关键作用 这些监管机制。然而，不幸的是，支持这一水平的直接证据 缺乏对内体信号传导机制的理解。在过去的四年里， 我的实验室致力于探索内吞过程中涉及的丰富的物理现象。我们有 揭示了免疫细胞内吞作用的新的物理机制，但我们提出的问题是普遍的 与多种细胞相关。我们的目的是测试一般假设，即内体是一个专门的 细胞信号转导的时空调节平台。这一建议突出了我们的两个 开发项目领域，旨在通过确定生物物理机制来测试这一假设， 内体信号调节两者都是由我们已经建立的生物物理工具实现的，这些工具允许我们操纵 并分析活细胞中内体的信号活性和动力学。一个研究方向聚焦于 关于内体膜上信号串扰的机制。我们这个研究方向的最终目标 是确定内体受体之间的物理相互作用导致其信号传导的机制， 串话通过开发一种新的方法，物理操纵受体之间的相互作用， 内体膜，我们将建立内体上受体簇之间的定量关系， 它们的信号串扰以及终点细胞响应。另一个研究项目涉及功能 内体运输在信号传导中的作用。我们第二个研究方向的最终目标是确定 内体的运输和亚细胞定位调节其信号功能的机制。 通过开发一种粒子报告系统，使我们能够磁性控制单个内体的运输， 并同时检测它们的信号活动，我们将揭示动力学之间的直接联系， 单个内体的机械和生物化学活性。提出的研究方向是可行的 通过纳米材料工程，定量物理测量和先进的光学技术的新集成， 技术，活细胞实验。从长远来看，我们将从内体开始扩大研究范围， 免疫细胞中的信号传导到其他细胞类型中。我们正在进行的和未来的研究方向分享 总体目标是建立活细胞内体信号传导的定量理解。

Abstract Endosomes, the membrane compartments inside living cells, are increasingly recognized as discrete “hubs” that regulate the network of cell signaling circuits in space and time. Physical phenomena like the clustering of proteins on endosome membranes and the active transport of endosomes are hypothesized to play a key role in these regulatory mechanisms. Unfortunately however, the direct evidence needed to support this level of mechanistic understanding of endosome signaling is lacking. Over the last four years, the research program of my lab has focused on exploring the wealth of physical phenomena involved in the endocytic process. We have uncovered new physical mechanisms of endocytosis in immune cells, but the questions we pose are of general relevance to many kinds of cells. We aim to test the general hypothesis that endosomes are a specialized platform for the spatiotemporal regulation of cellular signal transduction. This proposal highlights two of our developing project areas that are designed to test this hypothesis by identifying the biophysical mechanisms of endosome signaling regulation. Both are enabled by our established biophysical tools that allow us to manipulate and analyze the signaling activities and dynamics of endosomes in living cells. One research direction focuses on the mechanisms of signaling crosstalk on endosome membranes. Our ultimate goal for this research direction is to identify mechanisms by which physical interactions between endosomal receptors lead to their signaling crosstalk. By developing a novel approach that physically manipulates interactions between receptors on endosome membranes, we will establish the quantitative relationship between receptor clusters on endosomes, their signaling crosstalk, and the end-point cell response. The other research project addresses the functional roles of endosome trafficking in signaling. Our ultimate goal for this second research direction is to determine mechanisms under which the transport and subcellular location of endosomes regulate their signaling functions. By developing a particle reporter system that will allow us to magnetically control trafficking of single endosomes and simultaneously detect their signaling activities, we will reveal direct connection between the dynamical, mechanical and biochemical activities of individual endosomes. The proposed research directions are enabled by the novel integration of nanomaterial engineering, quantitative physical measurements, and advanced optical techniques, with live cell experiments. In the long term, we will expand our research scope from endosome signaling in immune cells to that in other cell types. Our ongoing and future research directions share the overarching goal of establishing a quantitative understanding of endosome signaling in living cells.