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

描述（由申请人提供）：多形细胞（PMN）在对入侵微生物的免疫应答中发挥不可或缺的作用。然而，活化的PMN可由于产生高毒性的促炎介质而损害宿主组织。为了了解更多关于控制PMN激活的机制，我们正在研究衔接分子如何协调免疫球蛋白（Fc-γ R）或β 2整合素（调节关键PMN功能的受体）的Fc受体启动的信号通路。我们有新的信息表明，造血衔接子SLP-76（含SH 2结构域的76 kD白细胞特异性磷蛋白）在Fc-γ R和整联蛋白连接后可诱导酪氨酸磷酸化。与这种衔接子在这些受体所使用的信号传导途径中的可能作用一致，SLP-76-/-PMN在体外显示出减少的Fc-γ R和缺乏整合素介导的活化，包括活性氧（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相关的衔接子PRAM-1（编码衔接子分子-1的PML-RAR α靶基因）和ADAP（粘附和脱颗粒促进衔接子蛋白）通过整合Fc-γ R和整合素介导的信号调节PMN功能。在这个建议中，我们将使用互补的方法来调查这一假设，并严格剖析这些分子在PMN激活的空间和生化要求。目标1中的结构-功能分析将确定SLP-76内的结构域，这些结构域是介导其细胞定位、与相关蛋白质的相互作用以及PMN特异性功能所需的。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，我们将产生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表达的缺失是否影响感染和自身免疫动物模型中的PMN活化。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）的新治疗方法提供见解。

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.