Regulation of Integrin Signaling by Adapter Proteins

整合素是细胞表面的二聚体受体，在细胞黏附和迁移中发挥重要作用。 对整合素功能至关重要的信号事件包括由其他细胞启动的第二信使级联 除了启动信号通路外，还调节其配体的整合素亲和力的表面受体 通过整合素本身的参与。我们和其他人已经发现，多分子的形成 接头蛋白形成的复合体对于整合素的信号传递(由内向外的信号传递)是必不可少的。 以及整合素的信号传递(自外向内信号传递)。我们的实验室长期以来一直对SH2感兴趣 含76 kDa结构域的白细胞磷蛋白(SLP-76)，一种造血限制性适应蛋白 这对免疫受体和整合素的功能都至关重要。本提案中描述的实验 将利用生化、成像、分子和遗传学方法来研究SLP-76的作用 及其相关分子在先天免疫系统和获得性免疫系统的细胞中的整合素反应。 这项工作将分为三个具体目标。第一个主题将探讨两国之间的诱导相互作用 SLP-76等蛋白对整合素结合及SLP-76亚细胞定位的影响 整合素在T细胞中发挥作用。将被检验的一个中心假设是，在中国有两个SLP-76的池 细胞，一个调节免疫受体信号，第二个调节整合素反应。 我们将进一步测试整合素途径需要SLP-76和3之间相互作用的概念 接头蛋白，ADAP(黏附和脱颗粒促进接头蛋白)，SKAP55(SrcKinase- 相关的55 kDa的磷酸蛋白)和RIAM(RAP1-GTP相互作用的接头分子)，以及这些 适配器共同形成一种复合体，将激活的Rap-1带到细胞表面。第二个目标 将在体内进行AIM 1的生化和成像研究，通过遗传产生 表达SLP-76或其相关分子突变的独特小鼠系 预测会选择性地影响T细胞免疫受体或整合素功能。第三个目标将延伸我们的工作 通过研究它们所协调的生物化学和分子事件来影响先天免疫系统 中性粒细胞中的适配分子，包括体外和体内。这个项目中描述的实验将使 广泛使用两个科学核心，并将广泛依赖于与项目负责人的互动 该计划的其他项目。我们希望这些研究将为多分子如何 复合体整合了导致适当免疫细胞反应的信号通路。

Integrins are dimeric cell surface receptors that play critical roles in cellular adhesion and migration. Signaling events critical for integrin function include second messenger cascades initiated by other cell surface receptors which modulate integrin avidity for their ligands in addition to signaling pathways initiated by engagement of integrins themselves. We and others have found that the formation of multimolecular complexes nucleated by adapater proteins is essential for both signaling to integrins (inside-out signaling) and signaling by integrins (outside-in signaling). Our laboratory has a long standing interest in the SH2 domain containing leukocyte phosphoprotein of 76kDa (SLP-76), a hematopoietic restricted adapater protein that is critical for function of both immunoreceptors and integrins. The experiments described in this proposal will make use of biochemical, imaging, molecular and genetic approaches to investigate the role of SLP-76 and its associated molecules in integrin responses in cells of both the innate and adaptive immune systems. The work will be divided into three specific aims. The first will explore the inducible interactions between SLP-76 and other proteins upon integrin engagement and the subcellular localization of SLP-76 during integrin function in T cells. One central hypothesis that will be tested is that there are two pools of SLP-76 in the cell, one which regulates immunoreceptor signaling and the second which regulates integrin responses. We will further test the notion that integrin pathway requires an interaction between SLP-76 and three adapter proteins, ADAP (Adhesion and Degranulation-promoting Adapter Protein), SKAP55 (SrcKinase- associated phosphoprotein of 55kDa), and RIAM (Rap1-GTP interacting adapter molecule), and that these adapters collectively nucleate a complex which brings activated Rap-1 to the cell surface. The second aim of this proposal will take the biochemical and imaging studies of Aim 1 in vivo by generating genetically unique murine lines in which mutations of SLP-76 or its associated molecules are expressed that are predicted to selectively impact T cell immunoreceptor or integrin function. The third aim will extend our work to the innate immune system by studying the biochemistry and molecular events coordinated by these adapter molecules in neutrophils, both ex vivo and in vivo. Experiments described in this project will make extensive use of both scientific cores and will rely extensively on interactions with the Project Leaders of the other projects of this program. We hope that these studies will provide new insights into how multimolecular complexes integrate signaling pathways leading to appropriate immune cell responses.