Analysis of adaptor protein (LAT) in TCR signaling

TCR对MHC-肽复合物的识别激活Src和Syk家族酪氨酸激酶， 诱导信号蛋白的磷酸化。其中一种显着磷酸化的蛋白质是LAT（接头 用于活化T细胞）。LAT是棕榈酰化的跨膜衔接蛋白，其结合Grb 2、Gads、PLC-1和Gad 3。 y1和其他信号分子，从而将这些分子募集到质膜以激活 下游信号事件，如Ras-MAPK激活和Ca 2+通量。既往LAT研究- 缺乏Jurkat细胞证明LAT对于TCP介导的信号转导是必需的， 棕榈酰化是LAT磷酸化和功能所必需的。LAT缺陷的小鼠有一个早期的阻滞， 胸腺细胞发育最近的研究表明，LAT在T细胞稳态中也起着重要作用。 表达不能结合PLC-γ 1的LAT突变体的小鼠发展为严重的自身免疫性疾病。基于 目前的信息和我们的初步研究结果，我们建议，通过耦合TCR参与Ras- LAT在调节T细胞活化、存活和增殖中起重要作用。 体内平衡有三个具体的目标旨在测试这一假设，并进一步了解如何 LAT在T细胞中起作用。在具体的目标1中，我们将使用小鼠，其中Lat基因可以通过Cre 重组酶，研究LAT在胸腺细胞发育过程中的作用。在具体目标2中，我们将诱导 在体内和体外缺失Lat基因以研究成熟T细胞中的LAT功能。我们将重点关注 LAT和LAT-PLC！TCR介导的信号传导、T细胞活化、稳态增殖 和细胞存活。在具体目标3中，我们将使用LAT条件性基因敲除小鼠来研究正常LAT是否 功能是外周中Treg细胞存活所必需的。我们还将研究Ca 2+途径的作用， 在Treg细胞发育和自身免疫中使用表达钙调神经磷酸酶的组成型活性形式的小鼠。 T细胞是我们免疫系统的核心组成部分。LAT是一种分子， 在T细胞活化中的作用。LAT功能的测定和TCR信号通路的进一步理解 可以促进设计合理的方法来增加或抑制自身免疫中的T细胞增殖， 过敏和组织器官移植。

Recognition of MHC-peptide complexes by the TCR activates Src and Syk family tyrosine kinases and induces phosphorylation of signaling proteins. One of the prominently phosphorylated proteins is LAT (linker for activation of T cells). LAT is a palmitoylated transmembrane adaptor protein that binds Grb2, Gads, PLC- y1, and other signaling molecules, thus recruiting these molecules to the plasma membrane to activate downstream signaling events, such as Ras-MAPK activation and Ca2+ flux. Previous studies with LAT- deficient Jurkat cells demonstrate that LAT is essential for TCP-mediated signal transduction and LAT palmitoylation is required for LAT phosphorylation and function. LAT-deficient mice have an early block in thymocyte development. Recent studies show that LAT also plays an important role in T cell homeostasis. Mice that express a LAT mutant that fails to bind PLC-y1 develop a severe autoimmune disease. Based on current information and our preliminary findings, we propose that, by coupling TCR engagement to Ras- MAPK activation and Ca2+ flux, LAT plays an important role in regulating T cell activation, survival, and homeostasis. There are three specific aims designed to test this hypothesis and to further understand how LAT functions in T cells. In specific aim 1, we will use mice, in which the Lat gene can be deleted by the Cre recombinase, to study the role of LAT during thymocyte development. In specific aim 2, we will induce deletion of the Lat gene in vivo and in vitro to study LAT function in mature T cells. We will focus on the role of LAT and the LAT-PLCy! interaction in TCR-mediated signaling, T cell activation, homeostatic proliferation, and cell survival. In specific aim 3, we will use LAT conditional knockout mice to study whether normal LAT function is required for Treg cell survival in the periphery. We will also investigate the role of the Ca2+ pathway in Treg cell development and autoimmunity using mice that express a constitutively active form of calcineurin. T cells are the central components of our immune system. LAT is one of the molecules that play essential roles in T cell activation. Determination of LAT function and further understanding TCR signaling pathway could facilitate the design of a rational approach to augment or inhibit T cell proliferation in autoimmunity, allergy, and tissue and organ transplantation.