Unravelling Mechanisms of Endosomal Signaling with Designer Nanomaterials

摘要 内小体是活细胞内的膜室，越来越多地被认为是离散的“中枢”，它 在空间和时间上调节细胞信号电路网络。物理现象，如聚集性 推测内吞体膜上的蛋白质和内容体的主动运输起关键作用。 在这些监管机制中。然而，不幸的是，支持这一水平的直接证据 缺乏对内体信号的机械性理解。在过去的四年里， 我的实验室一直专注于探索与内吞过程有关的丰富物理现象。我们有 发现了免疫细胞内吞作用的新物理机制，但我们提出的问题是一般性的 与多种细胞相关。我们的目标是检验这样一种普遍假设，即内小体是一种特殊的 细胞信号转导的时空调控平台。这项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说 内涵体信号调节。两者都是由我们现有的生物物理工具实现的，这些工具允许我们操纵 并分析活细胞内内体的信号活性和动力学。一个研究方向集中在 关于内吞体膜上信号串扰的机制。我们对这一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递的机制 相声。通过开发一种新的方法，物理地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， 它们的信号串扰和终端信元响应。另一个研究项目针对的是功能 内体运输在信号转导中的作用。我们第二个研究方向的最终目标是确定 内小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，使我们能够磁性地控制单个内小体的贩运 并同时检测它们的信号活动，我们将揭示动态的， 个体内小体的机械和生化活动。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光学的新集成 技术，与活细胞实验。从长远来看，我们将把我们的研究范围从内涵体扩大到 免疫细胞中的信号传递给其他类型的细胞。我们正在进行的和未来的研究方向共享 建立对活细胞中内体信号的定量理解的首要目标。

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.