CORECEPTOR MODIFICATION OF TCR TYROSINE KINASE SIGNALS

描述：(改编自申请者摘要)T细胞受体(TCR)抗原 认知诱导专业化的形成和稳定 T细胞：抗原提呈细胞(APC)交界处的“免疫突触”。 这一结点是由特定的招募和排除而产生的 来自接触区的蛋白质，是T细胞激活所必需的。预付款 在细胞生物学中已经揭示了质膜是由横向组成的 漂浮在甘油磷脂海洋中的相关“脂筏” 丰富的膜。脂筏富含一组细胞蛋白质， 与信号转导、细胞骨架重组和 蛋白质分类。我们假设脂筏/非脂筏的分配提供了 组织TCR和Co.的蛋白质分选的分子基础 刺激物、信号转导与T细胞的肌动蛋白细胞骨架 界面。我们最近的研究区分了两个明显受监管的 脂筏依赖的T细胞活化步骤：1)TCR参与诱导 TCR(和脂质内的信号转导)的磷酸化和浓度 RAFTS和2)TCR/CD48共刺激和LCK-SH3结构域依赖的迁移 将脂筏连接到TCR接触帽。而T细胞活化(TCR诱导 IL-2的产生)需要两个步骤，T细胞失活(TCR诱导 细胞凋亡)不受第二步中断的影响。因此，我们 假设TCR/介导的脂筏向血管内皮细胞募集 TCR联络地点为筏基平台的建造提供便利，该平台 调节TCR参与的功能结果。测试……的作用 组织TCR信号的RAFT/非RAFT膜分区 转导和T细胞上的肌动蛋白细胞骨架：APC接触帽，我们将 操纵与此相关的蛋白质的RAFT/非RAFT分配 处理并确定对T细胞信号和激活的影响(目标1)。 阐明TCR/co刺激的分子基础及其相互关系 在RAFT重组和TCR参与的功能结果之间 将：a)表征CD28、CD48和LFA-1对TCR的共刺激作用 脂筏重组和信号转导事件(目标2)；b)探索 TCR抗原结合特性的细微差异如何影响抗原诱导 RAFT重组、信号和TCR接触的功能结果(AIM 3)和；c)确定T细胞是否操纵脂筏的组成和动力学 在整个发育过程中为T细胞激活设定阈值(目标4)。这些 研究将有助于更好地理解TCR信号是如何调节到 调节不同的功能结果。脂筏成分的研究进展 RAFT重组的分子介体将提供新的靶点 对于以独立调节为目的的治疗，个体TCR诱导 反应如下：1)抑制不想要的T细胞激活 自身免疫、移植排斥和/或T细胞转化；2)促进 同种异体反应性和自身免疫T细胞的外周免疫耐受 针对次优呈现的增强肿瘤(或其他)疫苗 抗原。

DESCRIPTION: (Adapted from applicant's abstract) T cell receptor (TCR) antigen recognition induces the formation and stabilization of a specialized "immunological synapse" at the T cell: antigen presenting cell (APC) junction. This junction is generated by the recruitment and exclusion of particular proteins from the contact area and is required for T cell activation. Advances in cell biology have revealed that the plasma membrane is composed of laterally associated "lipid rafts" which float in a sea of otherwise glycerophospholipid rich membrane. Lipid rafts are enriched in a subset of cellular proteins and have been implicated in signal transduction, cytoskeletal reorganization and protein sorting. We hypothesize that lipid raft/non-raft partitioning provides the molecular basis for protein sorting which organizes the TCR and co stimulators, signal transducers and the actin cytoskeleton at the T cell:APC interface. Our recent studies discriminate two distinctly regulated lipid-raft-dependent T cell activation steps: 1) the TCR engagement-induced phosphorylation and concentration of TCR( and signal transducers within lipid rafts and 2) the TCR/CD48 co stimulation and Lck-SH3-domain-dependent migration of lipid rafts to the TCR contact cap. Whereas T cell activation (TCR induced IL-2 production) requires both steps, T cell inactivation (TCR-induced apoptosis) is unaffected by disruption of the second step. Therefore, we hypothesize that the TCR/mediated-mediated recruitment of lipid rafts to the TCR contact site facilitates the construction of a raft-based platform, which modulates the functional outcome of TCR engagement. To test the role of raft/non-raft membrane compartmentalization in organizing TCR signal transduction and the actin cytoskeleton at the T cell:APC contact cap, we will manipulate the raft/non raft partitioning of proteins involved in these processes and determine the effects on T cell signals and activation (Aim 1). To elucidate the molecular basis of TCR/co stimulation and the relationship between raft reorganization and the functional outcome of TCR engagement we will: a) characterize CD28, CD48 and LFA-1 costimulatory contributions to TCR lipid raft reorganization and signal transduction events (Aim 2); b) explore how subtle differences in TCR antigen binding properties affect antigen-induced raft reorganization, signals and the functional outcome of TCR engagement (Aim 3) and; c) determine if T cells manipulate lipid raft composition and dynamics throughout development to set thresholds for T cell activation (Aim 4). These studies will lead to a better understanding of how TCR signals are regulated to mediate distinct functional outcomes. Elucidation of lipid raft constituents and the molecular mediators of raft reorganization will provide novel targets for therapeutics aimed at independently modulating, individual TCR induced responses such as : 1) inhibiting unwanted T cell activation responsible for autoimmunity, graft rejection, and/or T cell transformation; 2) promoting peripheral tolerance in allograft reactive and autoimmune T cells and 3) potentiating tumor (or other) vaccines directed against sub optimally presented antigens.