Regulation of PMN activation by SLP-76, PRAM-1 and ADAP

描述（由申请人提供）：多形核细胞（PMN）在对入侵微生物的免疫反应中起着不可或缺的作用。然而，被激活的PMN会由于产生高毒性的促炎介质而损害宿主组织。为了进一步了解控制PMN激活的机制，我们正在研究接头分子如何协调Fc受体对免疫球蛋白（Fc-gamma）或β 2整合素（调节关键PMN功能的受体）启动的信号通路。我们有新的信息表明造血适配器SLP-76（含SH2结构域的白细胞特异性磷酸化蛋白76 kD）在fc - γ - mar和整合素连接后可诱导酪氨酸磷酸化。与该接头在这些受体使用的信号通路中的可能作用一致，SLP-76-/- pmn在体外表现出fc - γ - mar减少和缺乏整合素介导的激活，包括活性氧（ROS）产生缺陷。根据这些和相关的观察，我们假设SLP-76和SLP-76相关的接头PRAM-1（编码接头分子-1的pml - rar α靶基因）和ADAP（促进粘附和脱粒的接头蛋白）通过整合fc - γ和整合素介导的信号来调节PMN的功能。在本提案中，我们将使用互补的方法来研究这一假设，并严格剖析这些分子在PMN激活过程中的空间和生化要求。Aim 1中的结构-功能分析将定义SLP-76中介导其细胞定位、与相关蛋白相互作用和pmn特异性功能所需的结构域。在Aim 2中，我们将使用类似的方法进一步研究PRAM-1和ADAP在PMN中的作用。在Aim 3中，我们将生成并表征髓系限制性基因靶向小鼠，以确定体内SLP-76、PRAM-1和ADAP表达的缺失是否会影响感染和自身免疫动物模型中PMN的激活。这些研究将增加我们对PMN功能的了解，并可能为开发与PMN激活相关的人类疾病（包括免疫缺陷、感染和自身免疫）的新疗法提供见解。

DESCRIPTION (provided by applicant): Polymorphonuclear cells (PMN) play integral roles in the immune response to invading microorganisms. Activated PMN, however, can damage host tissues due to the production of highly toxic proinflammatory mediators. To learn more about the mechanisms controlling PMN activation, we are studying how adaptor molecules coordinate the signaling pathways initiated by Fc receptors for immunoglobulin (Fc-gammaR) or beta2 integrins, receptors that regulate critical PMN functions. We have new information that the hematopoietic adaptor SLP-76 (SH2 domain-containing Leukocyte-specific Phosphoprotein of 76 kD) is inducibly tyrosine phosphorylated following Fc-gammaR and integrin ligation. Consistent with a possible role for this adaptor in the signaling pathways used by these receptors, SLP-76-/-PMN demonstrate reduced Fc-gammaR and absent integrin-mediated activation in vitro, including defective production of reactive oxygen species (ROS). From these and related observations, we hypothesize that SLP-76, and the SLP-76-associated adaptors PRAM-1 (PML-RARalpha target gene encoding an Adaptor Molecule-1) and ADAP (Adhesion and Degranulation-promoting Adaptor Protein) regulate PMN function by integrating Fc-gammaR and integrin-mediated signals. In this proposal, we will use complementary approaches to investigate this hypothesis and to rigorously dissect the spatial and biochemical requirements for these molecules during PMN activation. Structure-function analyses in Aim 1 will define the domains within SLP-76 that are required to mediate its cellular localization, interaction with associated proteins and PMN-specific functions. In Aim 2, we will use similar approaches to further investigate the roles of PRAM-1 and ADAP in PMN. In Aim 3, we will generate and characterize myeloid lineage-restricted gene-targeted mice to determine whether the loss of SLP-76, PRAM-1 and ADAP expression in vivo influences PMN activation in animal models of infection and autoimmunity. These investigations will increase out understanding of PMN function and may provide insights into the development of new treatments for human disorders associated with PMN activation, including immunodeficiency, infection and autoimmunity.