Regulation of TCR Signaling by Sts-1 and Sts-2

描述（由申请人提供）：允许T细胞产生有效免疫应答的相同特性可以针对宿主组织，引发自身免疫应答。有趣的是，T细胞自身反应性通常是T细胞内信号通路失调的结果。因此，了解不同的自身免疫性疾病的病因将需要彻底和综合的理解控制T细胞活化的机制。我研究的长期目标是了解T细胞活化的调节。 目前，我的实验室正在研究两种相关的蛋白质Sts-1和Sts-2如何协同作用来负调节T细胞信号通路。Sts蛋白具有独特的模块结构，具有N-末端泛素相互作用结构域（乌巴）、中心蛋白-蛋白相互作用结构域（SH 3）和与磷酸甘油酸酯酶（PGM）同源的C-末端区域。认识到Sts蛋白在调节TCR信号通路中的作用来自对缺乏Sts-1和-2的小鼠的分析。来自Sts-1/2-/-小鼠的T细胞响应于TCR刺激而显著过度增殖。在多发性硬化症小鼠模型中，这种过度增殖表型伴随着TCR下游信号传导途径的激活增加，细胞因子产生水平升高，以及Sts-1/2-/-小鼠对自身免疫的易感性增加. 在我们正在进行的努力，以表征的Sts蛋白的功能，我们最近发现了一种新的蛋白酪氨酸磷酸酶活性与Sts的PGM域。有趣的是，Sts磷酸酶结构域在一级氨基酸序列和重要的催化特征上与经典的PTP没有相似性。再加上没有已知的PTP包含乌巴或SH 3结构域的事实，我们的研究结果表明，Sts蛋白在T细胞内的细胞内信号小生境中运作，该小生境与经典PTP是分离和不同的。本提案中概述的实验旨在解决Sts-1和Sts-2的潜在功能和作用机制。我们的具体目标是：1。确定Sts蛋白如何通过调节Zap-70来调节T细胞活化阈值。2.确定三个Sts模块结构域（乌巴、SH 3、PGM）如何协同负调节TCR信号通路。我们将使用生物化学，生物物理学和细胞生物学方法的组合来实现我们的目标。本文所述研究的完成将帮助我们建立Sts蛋白如何合作负调控TCR信号通路的模型。 公共卫生相关性：当免疫系统内的正常调节机制失效时，就会出现自身免疫性疾病。开发将预防或治愈自身免疫性疾病的疗法将需要对控制免疫反应的机制有全面和综合的了解。该项目的重点是了解T细胞受体信号传导的一对密切相关的负调节因子Sts-1和Sts-2的功能和作用机制。

DESCRIPTION (provided by applicant): The same properties that allow T cells to mount an effective immune response can be turned against host tissue, provoking an autoimmune response. Intriguingly, T cell auto-reactivity is often the result of deregulated signaling pathways within T cells. Thus, understanding the etiology of different autoimmune diseases will require a thorough and integrated understanding of the mechanisms that control T cell activation. The long-term objective of my research is to understand the regulation of T cell activation. Currently, my laboratory is studying how two related proteins, Sts-1 and Sts-2, act in concert to negatively regulate T cell signaling pathways. The Sts proteins have a unique modular structure, with an N- terminal ubiquitin-interacting domain (UBA), a central protein-protein interaction domain (SH3), and a C- terminal region with homology to the enzyme phosphoglycerate mutase (PGM). The realization that the Sts proteins have a role in regulating TCR signaling pathways emerged from an analysis of mice lacking Sts-1 and -2. T cells from Sts-1/2-/- mice dramatically hyper-proliferate in response to TCR stimulation. This hyper- proliferative phenotype is accompanied by increased activation of signaling pathways downstream of the TCR, elevated levels of cytokine production, and increased susceptibility of Sts-1/2-/- mice to autoimmunity in a mouse model of multiple sclerosis. In our ongoing effort to characterize the functions of the Sts proteins, we recently discovered a novel protein tyrosine phosphatase activity associated with the Sts PGM domain. Intriguingly, the Sts phosphatase domain shows no similarity to classical PTPs in primary amino acid sequence and important catalytic features. Coupled with the fact that no known PTP contains a UBA or SH3 domain, our results suggest that the Sts proteins operate in an intracellular signaling niche within T cells that is separate and distinct from classical PTPs. The experiments outlined in this proposal are designed to address the underlying function(s) and mechanism(s) of action of the Sts-1 and Sts-2. Our Specific Aims are: 1. Determine how the Sts proteins regulate T cell activation thresholds via regulation of Zap-70. 2. Determine how the three Sts modular domains (UBA, SH3, PGM) cooperate to negatively regulate TCR signaling pathways. We will use a combination of biochemical, biophysical, and cell biological approaches to accomplish our goals. Completion of the studies described herein will help us build a model of how the Sts proteins cooperate to negatively regulate TCR signaling pathways. PUBLIC HEALTH RELEVANCE: Autoimmune diseases arise when normal regulatory mechanisms within the immune system fail. Developing therapies that will prevent or cure autoimmune diseases will require a thorough and integrated understanding of the mechanisms that control the immune response. This project focuses on understanding the function(s) and mechanism(s) of action of a closely related pair of negative regulators of T cell receptor signaling, Sts-1 and Sts-2.