Phagocytosis in Pulmonary Alveolar Macrophages

肺泡巨噬细胞的吞噬作用

• 批准号: 7088897
• 负责人: STEVEN M GREENBERG
• 金额: $ 38.27万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7088897
• 关键词: RNA interference; actin binding protein; actins; alveolar macrophages; antibody receptor; biological signal transduction; bone marrow; computer program /software; cytoskeleton; dynamin; enzyme substrate; genetically modified animals; immunoglobulin G; laboratory mouse; phagocytosis; phosphorylation; protein protein interaction; protein structure function; protein tyrosine kinase; proteomics; small interfering RNA; tissue /cell culture

DESCRIPTION (provided by applicant): Phagocytosis is a phylogenetically ancient response to particulate stimuli adapted by specialized cells of the immune system. Among the best characterized phagocytic receptors are those that recognize the Fc portion of IgG (FCyRs). Phagocytosis via FCyRs requires the recruitment and activation of Syk, a tyrosine kinase expressed predominantly in hematopoietic cells. In this proposal we outline approaches to identify and characterize downstream targets of Syk that initiate or modify phagocytic signaling. Using proteomics to probe the "phosphotyrosome" of phagocytosis, we have identified proteins that either undergo enhanced tyrosine phosphorylation, or associate with phosphotyrosyl-containing proteins, during phagocytosis. Among these proteins are moesin, a member of the ERM family of actin-binding proteins and Abpl, an adaptor for F-actin, and dynamin. We hypothesize that moesin and ezrin, 2 ERM family members, stabilize the association of the actin based cytoskeleton with the plasma membrane in nascent pseudopods, thereby contributing to pseudopod rigidity. As both proteins contain functional immunoreceptor tyrosine-based activation motifs (ITAMs) that potentially bind Syk, they may act as direct transducers of the phagocytic signal. In Specific Aim I, we outline approaches to test this hypothesis. These experiments include use of software we helped design to predict effective siRNA sequences. In Specific Aim II, we will determine whether Abpl and/or its family members, cortactin and HS1, coordinate the delivery of cytoskeletal components with endo-/exocytic machinery (dynamin). As we have previously proposed a "two compartment" model of phagocytosis whereby the programs of cytoskeletal assembly and membrane trafficking both contribute to phagocytosis, Abp1 and its homologs would fulfill the role of molecular coordinator of these events.

描述（由申请人提供）：吞噬作用是对由免疫系统专业细胞改编的颗粒刺激的系统发育反应。在最佳特征的吞噬受体中，有识别IgG（FCYR）FC部分的受体。通过FCYRS的吞噬作用需要Syk的募集和激活，Syk是一种主要在造血细胞中表达的酪氨酸激酶。在此提案中，我们概述了识别和表征启动或修改吞噬信号传导的SYK下游目标的方法。使用蛋白质组学来探测吞噬作用的“磷酸化体”，我们已经鉴定出蛋白质在吞噬作用期间，蛋白质可以增强酪氨酸磷酸化，或与含磷酸酪糖基的蛋白质相关。这些蛋白质中有Moesin，Moesin是肌动蛋白结合蛋白的ERM家族和ABPL的成员，F-肌动蛋白的适配器和Dynamin。我们假设Moesin和Ezrin是2个ERM家族成员，它稳定了基于肌动蛋白的细胞骨架与新生假脚架中质膜的关联，从而有助于假脚架刚性。由于两种蛋白质都包含可能结合SYK的功能性免疫受体酪氨酸活化基序（ITAMS），因此它们可以充当吞噬信号的直接传感器。在特定目标I中，我们概述了检验该假设的方法。这些实验包括使用软件，我们帮助设计以预测有效的siRNA序列。在特定的AIM II中，我们将确定ABPL和/或其家人Cortactin和HS1是否协调了细胞骨架成分与内部/外卵细胞机械（Dynamin）的递送。正如我们先前提出的吞噬作用的“两个隔室”模型，在该模型中，细胞骨架组装和膜运输程序既有助于吞噬，ABP1及其同源物都可以履行这些事件的分子协调剂的作用。