RAS PROTEINS IN T CELL ACTIVATION AND DIFFERENTIATION

说明(摘自申请摘要)：的长期目标 这项拟议的研究是为了表征T细胞的效力是如何 受体(TCR)信号影响小分子RAS家族的活性 GTP酶。‘I’CR信号将通过改变CD45的贡献来查看 蛋白酪氨酸磷酸酶和通过使用不同亲和力的配体 TCR。这些研究将探索一种假设，即小GTP酶RAS和 相关蛋白RAPL不是相互孤立地发挥作用，而是保持 在紧密的功能关系中可以有效地整合和修改 TCR复合体诱导的信号转导事件。申请人 假设取决于CD45的异构体和T细胞的强度 细胞受体连接，拮抗或协同排列 包括RAS和Rap1之间的关系，以及这些不同的关系 这可能会影响T细胞早期发育等淋巴细胞行为， 成熟细胞分化为Th1或‘i’h2辅助细胞亚群，以及 内存T细胞池的生成。在目标1中，生化和功能 实验将检测单个CD45亚型对RAS和RAPL的影响 关于他们直接的下游目标和直接的上游目标 刺激物、Raf激酶和鸟嘌呤核苷酸交换因子 (GEFS)。因为个人..。CD4：亚型被认为是 差异修饰T细胞对TCR诱导信息的反应性 在这些研究中获得的将在目标2中模拟方法，在该方法中 高亲和力野生型多肽或低亲和力TCR刺激 改变的多肽配基，将被分析。特别是，以下是这些 刺激，申请者将评估RAS和 RAPL，并检测RAP1的功能特性以增强或抑制RAS- 丝裂原活化蛋白激酶(MPK)的信号转导作用。申请人 计划最终提供占主导地位的消极或构成积极的 RAS或RAP1的突变体转化原代T细胞并检测其对T细胞的杀伤作用 干扰免疫过程中发生的功能极化过程 回应。了解控制激活的分子机制 而幼稚T辅助细胞的分化对于 各种免疫状况，包括过敏、传染性和 自身免疫性疾病。此外，T调节的基础研究 小分子GTP酶介导的淋巴细胞在癌症领域具有广泛的适用性 发病机制。

DESCRIPTION (adapted from application abstract): The long term objective of the proposed research is to characterize how the potency of the T cell receptor (TCR) signals affects the activity of the Ras family of small GTPases. 'I'CR signals will be viewed by altering the contribution of the CD45 protein tyrosine phosphatase and by using ligands of varying affinities for the TCR. Thee studies will explore the hypothesis that small GTPases Ras and related protein Rapl do not act in isolation from each other but rather remain in close functional relationships which may effectively integrate and modify signal transduction events induced by the TCR complex. The applicant hypothesizes that depending on the isoform of CD 45 and the strength of the T cell receptor ligation, either antagonistic or synergistic arrangements between Ras and Rap1 are included, and that these different relationships which may influence lymphocyte behaviors such as T cell early development, differentiation of matured cells into Th1 or 'I'h2 helper subsets, and the generation of memory T cell pools. In aim 1, the biochemical and functional experiments will examine the effect s of single CD45 isoforms on Ras and Rapl with respect to their immediate downstream targets and the direct upstream stimulators, the Raf kinases and the guanine nucleotide exchange factors (GEFs) respectively. Because individual.. CD4: isoforms are believed to differentially modify responsiveness of T cells to TCR induction information obtained in these studies will model approaches in aim 2 in which the effects of TCR stimulation with high affinity wild type peptide or low affinity altered peptide ligand, will be analyzed. In particular, following, these stimulations, the applicant will evaluate biochemical activities of Ras and Rapl, and examine functional properties of RAP1 to enhance or suppress Ras- signaling effects on mitogen activated protein kinase (MPK). The applicant plans to eventually deliver the dominant negative or constitutive active mutants of Ras or Rap1 into primary T cells and to test their potential to interfere with the functional polarization processes occurring during immune response. Understanding the molecular mechanisms controlling the activation and differentiation of naive T helper cells is crucial with regard to a variety of immunological conditions including allergic, infectious and autoimmune diseases. In addition, basic studies on the regulation of T lymphocytes by small GTPases have broad applicability to the field of cancer pathogenesis.