CORECEPTOR MODIFICATION OF TCR TYROSINE KINASE SIGNALS

描述：（改编自申请人摘要）T细胞受体（TCR）抗原 识别诱导专业化的形成和稳定 在T细胞：抗原呈递细胞（APC）连接处的“免疫突触”。 这种连接是由特定的 蛋白质从接触区，并需要T细胞活化。进展 在细胞生物学中已经揭示了质膜是由横向的 相关的“脂筏”漂浮在甘油磷脂的海洋中， 丰富的膜脂筏富含一组细胞蛋白， 与信号转导、细胞骨架重组和 蛋白质分选我们假设脂筏/非脂筏分配提供了 蛋白质分选的分子基础是组织TCR和Co T细胞上的刺激物、信号转导物和肌动蛋白细胞骨架：APC 接口.我们最近的研究区分了两种明显受调控的 脂筏依赖性T细胞活化步骤：1）TCR增殖诱导的T细胞活化。 TCR（和脂质内的信号转导子）的磷酸化和浓度 2）TCR/CD 48共刺激和Lck-SH 3结构域依赖性迁移 TCR接触帽上的脂筏而T细胞活化（TCR诱导的 IL-2产生）需要两个步骤，T细胞灭活（TCR诱导的 细胞凋亡）不受第二步骤的破坏的影响。所以我们 假设TCR/介导的脂筏募集到 TCR接触点便于建造筏基平台， 调节TCR接合的功能结果。测试的作用 组织TCR信号的筏/非筏膜区室化 转导和肌动蛋白细胞骨架在T细胞：APC接触帽，我们将 操纵参与这些蛋白质的筏/非筏分配， 处理并确定对T细胞信号和活化的影响（目的1）。 阐明TCR/共刺激的分子基础及TCR/共刺激的相互关系， 在筏重组和TCR参与的功能结果之间， 将：a）表征CD 28、CD 48和LFA-1对TCR的共刺激贡献 脂筏重组和信号转导事件（目的2）; B）探索 TCR抗原结合特性的细微差异如何影响抗原诱导的 筏重组，信号和TCR参与的功能结果（Aim 3)和c）确定T细胞是否操纵脂筏组成和动力学 在整个发展过程中，以设定T细胞活化的阈值（目标4）。这些 研究将有助于更好地了解TCR信号是如何调节的， 介导不同的功能结果。脂筏组分的解析 而RAFT重组的分子介导物将提供新的靶点 对于旨在独立调节单个TCR诱导的 反应，如：1）抑制不需要的T细胞活化， 自身免疫、移植排斥和/或T细胞转化; 2）促进 同种异体移植反应性和自身免疫性T细胞的外周耐受和3） 针对次优呈递的增强肿瘤（或其它）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.