The Role of Unc119 in T Cell Antigen Receptor Signaling1

Unc119 在 T 细胞抗原受体信号转导中的作用1

• 批准号: 6770739
• 负责人: Rafeul Alam
• 金额: $ 37.9万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-15 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6770739
• 关键词: CD3 molecule; Retroviridae; T cell receptor; binding sites; biological signal transduction; clinical research; enzyme linked immunosorbent assay; gene induction /repression; genetic screening; genetically modified animals; helper T lymphocyte; human genetic material tag; human subject; immunodeficiency; immunogenetics; laboratory mouse; lymphopenia; pathologic process; patient oriented research; polymerase chain reaction; protein tyrosine kinase; thymopoietin; thymus disorder; transfection /expression vector; western blottings; yeast two hybrid system

DESCRIPTION (provided by applicant): T cells play a central role in immune response. The first step in the signaling mechanism of the T cell receptor (TCR) is the activation of Src family of tyrosine kinases--Lck and Fyn. Although much is known about signal transduction mechanism of TCR, the exact molecular mechanism of Lck and Fyn activation is unknown. Through yeast two-hybrid screening we have recently cloned a novel SH3 ligand called Unc119. In preliminary results we show that Unc119 is associated with the TCR complex (CD3 and CD4) activates Lck and Fyn in vitro and in vivo. Unc119 deficient cells are unable to activate Lck and Fyn, fail to produce IL-2 and proliferate poorly. The objective of this research proposal is to study the signaling function of Unc119 for T cell function and the role of Unc119 in the pathogenesis of idiopathic CD4 lymphopenia, a rare immunodeficiency disorder. Our specific aims are 1). To study the molecular mechanism of Unc119 activation of Lck/Fyn. 2). To examine the importance of Unc119 for T cell differfentiation and function. 3). To investigate the role of Unc119 in the pathogenesis of idiopathic CD4 lymphopenia. We will map the CD4 and kinase (Lck/Fyn) binding sites of Unc119 through mutational approaches and study the importance of these sites for kinase activation. In order to establish the biological relevance, we will generate Unc119 knockout mice and study thymopoiesis and T cell function. We have identified one ICL patient with Unc119deficiency and impaired Lck activation. This patient has an Arg50-->Lys mutation in the coding sequence and has another mutation in the 3' untranslated region. We will screen ICL patients nationwide through preestablished collaboration and examine the presence of this and other mutations. We will examine the functional relevance of these mutations by studying translation and decay of the protein. The biological relevance will be studied by expressing the mutated gene in normal T cells and vice versa. The proposal is important because it describes the identification and characterization of a novel activator of TCR-associated tyrosine kinases. Further, it examines the molecular mechanism of idiopathic CD4 lymphopenia, which may pave the way to gene therapy for this rare immunodeficiency disorder.

描述（由申请人提供）：T 细胞在免疫反应中发挥核心作用。 T 细胞受体 (TCR) 信号传导机制的第一步是激活酪氨酸激酶 Src 家族 - Lck 和 Fyn。尽管人们对TCR的信号转导机制了解很多，但Lck和Fyn激活的确切分子机制尚不清楚。通过酵母双杂交筛选，我们最近克隆了一种新型SH3配体，称为Unc119。在初步结果中，我们表明 Unc119 与 TCR 复合物（CD3 和 CD4）相关，在体外和体内激活 Lck 和 Fyn。 Unc119 缺陷细胞无法激活 Lck 和 Fyn，无法产生 IL-2 并且增殖不良。本研究计划的目的是研究 Unc119 对 T 细胞功能的信号传导功能以及 Unc119 在特发性 CD4 淋巴细胞减少症（一种罕见的免疫缺陷性疾病）发病机制中的作用。我们的具体目标是 1)。研究Unc119激活Lck/Fyn的分子机制。 2）。研究 Unc119 对 T 细胞分化和功能的重要性。 3）。探讨 Unc119 在特发性 CD4 淋巴细胞减少症发病机制中的作用。我们将通过突变方法绘制 Unc119 的 CD4 和激酶 (Lck/Fyn) 结合位点图谱，并研究这些位点对于激酶激活的重要性。为了建立生物学相关性，我们将生成 Unc119 敲除小鼠并研究胸腺生成和 T 细胞功能。我们已确定一名 ICL 患者存在 Unc119 缺陷且 Lck 激活受损。该患者的编码序列中有一个 Arg50-->Lys 突变，并且 3' 非翻译区有另一个突变。我们将通过预先建立的合作在全国范围内筛查 ICL 患者，并检查这种突变和其他突变的存在。我们将通过研究蛋白质的翻译和衰变来检查这些突变的功能相关性。将通过在正常 T 细胞中表达突变基因来研究生物学相关性，反之亦然。该提案很重要，因为它描述了 TCR 相关酪氨酸激酶的新型激活剂的鉴定和表征。此外，它还研究了特发性 CD4 淋巴细胞减少症的分子机制，这可能为这种罕见的免疫缺陷病的基因治疗铺平道路。