Control of T cell activation by the TSAd adapter protein

描述(申请人提供)：T细胞对微生物、肿瘤细胞和正常自身细胞的反应，如在自身免疫性疾病中发生的，其特征是T细胞克隆性增殖和针对相关异源或自身抗原的效应器和记忆功能的发展。因此，为了设计更有效的药物治疗方法来治疗传染病、癌症和自身免疫，了解不同T细胞表面受体接收的信号能够指示这些反应的细胞内机制是重要的。与其他类型的细胞一样，许多不同类别的细胞内分子参与T细胞的信号转导。其中包括细胞质适配蛋白，它们通过与催化活性分子形成信号复合体来发挥信号传递功能。最近在T细胞中发现的一种适配蛋白是T细胞特异性适配蛋白(TSAd)，在小鼠中也称为LCK相关适配蛋白(LAD)。该分子在T细胞因子的诱导中起重要作用，白介素2(IL-2)驱动T细胞的增殖和记忆的形成，干扰素-γ(干扰素-γ)参与T辅助型I型效应T细胞的功能。TSAd如何参与细胞内信号转导尚不清楚。然而，我们已经证明，TSAd是一种非典型的接头蛋白，具有明显的核定位，可能至少部分地作为T细胞基因转录的直接调节因子。这项建议的长期目标是更详细地了解TSAD如何控制目标基因的转录。在这些研究中，我们将重点研究蛋白质的两个不同的结构域，即Src Homology-2(SH2)结构域和氨基末端区域。在一个特定的目标中，我们将通过识别P95-100 kDa的单个酪氨酸磷酸化配体的能力来检验SH2结构域作为TSAd核输入和转录活性的动态调节因子的假设。在第二个特定目标中，我们将测试这一假设，即氨基末端区域作为一个模块，赋予TSAd识别目标基因启动子中特定DNA序列的能力。这两个结构域对于TSAd在原代T细胞中的转录功能以及对整个动物的正常T细胞免疫的重要性将在本提案的第三个特定目标中进行测试。总之，这些研究将导致对T细胞基因转录控制机制的新见解，此外，还应突出某些类型的T细胞介导的免疫疾病中异常T细胞反应可能被预防的方法。

DESCRIPTION (provided by the applicant): T cell responses to microorganisms, neoplastic cells and normal self cells, as occurs in autoimmune diseases, are characterized by T cell clonal expansion and development of effector and memory function which is targeted toward the relevant foreign or self antigen. So as to design more effective drug therapies for the treatment of infectious diseases, cancer, and autoimmunity, it is important to understand the intracellular mechanisms by which signals received by different T cell surface receptors are able to instruct these responses. As in other cell types, numerous different classes of intracellular molecules are involved in signal transduction in T cells. Amongst these are cytoplasmic adapter proteins that function in signaling through the formation of signaling complexes with catalytically active molecules. One recently described adapter protein in T cells is the T cell-specific adapter protein (TSAd), also known as LCK-associated adapter protein (LAD) in mice. This molecule plays an important role in the induction of the T cell cytokines, interleukin-2 (IL-2), which drives T cell proliferation and memory formation, and interferon gamma (IFN-gamma), which is involved in the function of T helper-I-type effector T cells. How TSAd participates in intracellular signaling is unknown. However, we have demonstrated that TSAd is an atypical adapter protein that has a predominant nuclear localization that probably acts, at least in part, as a direct regulator of T cell gene transcription. The long-term objectives of this proposal are to understand in greater detail how TSAd controls the transcription of target genes. In these studies, we will focus upon two different domains of the protein, the Src homology-2 (SH2) domain and the amino-terminal region. In one Specific Aim, we will test the hypothesis the SH2 domain functions as a dynamic regulator of TSAd nuclear import and transcription activity through its ability to recognize a single tyrosine-phosphorylated ligand of p95-100 kDa. In a second Specific Aim, we will test the hypothesis that the amino-terminal region functions as a module that confers upon TSAd an ability to recognize specific DNA sequences in target gene promoters. The importance of these two domains for the transcription function of TSAd in primary T cells and for normal T cell immunity in whole animals will be tested in a third Specific Aim of this proposal. Together, these studies should lead to novel insights into mechanisms of T cell gene transcription control and, in addition, should highlight means by which aberrant T cell reactivity in certain types of T cell-mediated immune disease might be prevented.