Endocytic dynamics and surface emergent property of leukocyte Integrins

项目摘要 白细胞整合素的调节和分选是细胞粘附和极性的基本问题， 对各种炎症和自身免疫性疾病有很大的意义，但与其他疾病相比， 成纤维细胞中的细胞粘附受体。我们建议研究白细胞整合素的分选 以及在免疫细胞粘附和迁移中起关键作用的四跨膜蛋白。我们建议其 动态分选依赖于一种新的F-BAR依赖机制，该机制不仅依赖于曲率， 而是在特定范围的浅曲率上。我们还建议， 中尺度模式，这些受体组装，包括传播梯度和皮质 振荡，将贩运事件与细胞极性联系起来。具体而言，在目标1中，我们计划描述 整合素αMβ2等潜在跨膜蛋白的表面表达和动力学 和CD 81后，系统地鉴定和验证膜货物介导的内吞途径， F-BAR蛋白FBP 17和CIP 4使用非偏倚蛋白质组学方法。在目标2中，我们的目标是分离出 的膜曲率和张力使用明确的体外系统，并确定其对F- BAR膜结合和微管结合。我们将采用基于纳米棒的支持双层系统， 评估F-BAR蛋白是否感知曲率。我们还将检验膜微管可能 需要脂质分选和活性膜机械。这些实验将提供一个定量的 F-BAR蛋白如何在没有疏水插入的情况下使膜形成微管的生物物理学理解 其他BAR蛋白通常使用的机制。在目标3中，我们将剖析 通过审查自发移徙或监禁下的移徙，改变了贩运的方式。我们尤其 将研究极化膜受体梯度形成的机制。共同地，结合 先进的单细胞成像，基因组编辑，蛋白质组学和体外重建，拟议的研究 将通过复杂的协调，揭示白细胞整合素的调节和功能的关键见解 以及在多个空间和时间尺度上运作的调节机制， 研究了

Project Summary Regulation and sorting of leukocyte integrins are fundamental questions in cell adhesion and polarity that has great implication for various inflammatory and autoimmune diseases, but it has been poorly studied compared to cell adhesion receptors in fibroblast cells. We propose to investigate the sorting of leukocyte integrins and tetraspanin proteins that play critical role in immune cell adhesion and migration. We propose its dynamic sorting depends on a novel F-BAR-dependent mechanism that not only depends on curvature, but on a specific range of shallow curvature. We also propose that this mechanism is governing the mesoscale pattern these receptors are assembled, including propagating gradients and cortical oscillations, which link trafficking events to cell polarity. Specifically, in Aim 1, we plan to characterize surface expression and dynamics of these potential transmembrane protein cargos including integrin αMβ2 and CD81 after systematically identify and validate membrane cargos for the endocytic pathway mediated by F-BAR protein FBP17 and CIP4 using nonbiased proteomic approach. In Aim 2, we aim to isolate the factor of membrane curvature and tension using well-defined in vitro systems and to determine their effects on F- BAR membrane binding and tubulation. We will employ a nanobar-based supported bilayer system to critically evaluate if F-BAR protein senses curvature. We will also test the hypothesis that membrane tubulation may require lipid sorting and active membrane mechanics. These experiments will provide a quantitative biophysical understanding of how F-BAR proteins tubulate membranes without the hydrophobic insertion mechanisms commonly used by other BAR proteins. In Aim 3, we will dissect the functional consequences of the altered trafficking by examining spontaneous migration or migration under confinement. In particular, we will investigate the mechanism for polarized membrane receptor gradient formation. Collectively, combining advanced single cell imaging, genome-editing, proteomics, and in vitro reconstitution, the proposed research will shed key insights into the regulation and function of leukocyte integrins through sophisticated coordination and regulatory mechanisms operating at multiple spatial and temporal scales that have not yet been investigated.