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发挥着不可或缺的作用。然而，激活的PMN可以由于产生剧毒的促炎介质而损害宿主组织。为了更多地了解控制PMN激活的机制，我们正在研究接头分子如何协调免疫球蛋白Fc受体(Fc-Gammar)或β2整合素启动的信号通路，这是调节PMN关键功能的受体。我们有了新的信息，在Fc-Gammar和整合素连接后，造血适配器SLP-76(含有SH2结构域的76kD的白细胞特异性磷酸蛋白)被诱导酪氨酸磷酸化。与该适配器在这些受体所使用的信号通路中的可能作用一致，SLP-76-/-PMN在体外显示Fc-Gammar减少和整合素介导的激活缺失，包括活性氧物种(ROS)的缺陷产生。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-RARpha靶基因)和ADAP(黏附和脱颗粒促进接头蛋白)通过整合Fc-Gammar和整合素介导的信号来调节PMN的功能。在这个提案中，我们将使用互补的方法来研究这一假说，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中调节其细胞定位、与相关蛋白质相互作用和PMN特定功能所需的结构域。在目标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。在目标3中，我们将建立和鉴定髓系限制基因靶向的小鼠，以确定体内SLP-76、PRAM-1和ADAP表达的缺失是否影响感染和自身免疫动物模型中PMN的激活。这些研究将增加对PMN功能的了解，并可能为开发与PMN激活相关的人类疾病的新疗法提供见解，包括免疫缺陷、感染和自身免疫。

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.