Novel mechanisms of TCR quality control

TCR质量控制的新机制

• 批准号: 8303743
• 负责人: Linda M Hendershot
• 金额: $ 7.84万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-07 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8303743
• 关键词: Address; Anabolism; Antibodies; Attention; Biologic Characteristic; Biological Assay; Biological Models; CD3 Antigens; Cell Culture Techniques; Cell Surface Receptors; Cell surface; Cells; Characteristics; Charge; Client; Complex; Data; Development; Endoplasmic Reticulum; Ensure; Evolution; Extracellular Domain; Immune response; Immune system; In Vitro; Individual; Integral Membrane Protein; Jaw; Kinetics; Literature; Measures; Membrane; Methods; Modeling; Molecular; Molecular Chaperones; Monitor; Organism; Pathway interactions; Play; Polyproteins; Process; Property; Proteins; Proteolysis; Quality Control; Receptor Cell; Reporting; Resolution; Role; Site; T-Cell Receptor; Techniques; Transmembrane Domain; Travel; Vertebrates; Work; base; disulfide bond; extracellular; in vivo; insight; interdisciplinary approach; invariant chain; membrane assembly; novel; oxidation; polypeptide; protein folding; receptor; research study; stoichiometry

DESCRIPTION (provided by applicant): The ¿¿T-cell receptor is essential for major functions of the adaptive immune system and is one of the most complex cell surface receptors. It is composed of eight polypeptide chains that must be assembled in the ER in the proper stoichiometry for it to perform its vital functions. As such, its assembly poses a formidable task for the ER quality control machinery. Although a large body of literature exists on the assembly and quality control of the ¿¿TCR, these efforts have focused primarily on the unusual transmembrane domains of the individual chains. These possess charged residues that, when unpaired, accelerate degradation of the ¿¿TCR chains and are believed to drive assembly. However, the basis of this presumed "integral membrane quality control" step has not been elucidated. Furthermore, very little attention has been directed to possible roles for the lumenal portions of this receptor, which are likely to be the regions scrutinized by the known quality control machinery of the ER. To remedy this deficiency, we propose to combine biophysical and cell based studies to obtain high resolution structural and kinetic data on the folding and assembly of the ¿¿TCR that can be correlated with checkpoints in the cell. Our preliminary data obtained from these approaches have already revealed two unanticipated features of the TCR ¿-chain. We find that its constant domain is unstructured in the absence of association with the ¿- chain and that its transmembrane region is not integrated into the ER membrane when expressed alone. These two features are very likely to provide checkpoints in the quality control of receptor assembly. These preliminary insights will be expanded in order to obtain an integrated view of the ER mechanisms that aid and monitor TCR biosynthesis allowing only properly assembled receptors to be expressed on the cell surface. PUBLIC HEALTH RELEVANCE: Although there has been much progress in identifying components of the ER quality control machinery, the underlying mechanisms for executing them remain poorly understood. This is particularly true for transmembrane proteins that control important functions in multicellular organisms and are often pharmacological targets. We propose studies to decipher novel aspects in the assembly and quality control of the essential T cell antigen receptor (TCR), one of the most complex cell surface receptors known. We chose the TCR because strict quality control checkpoints are known to scrutinize the assembly of this eight-chain receptor, yet the underlying molecular mechanisms are not well understood. The role of its lumenal domains in quality control has not been adequately investigated, and a putative "transmembrane quality control" step has remained vague. Both layers of quality control will be addressed within our proposed project. The mechanistic insights gained from our proposed combination of in vitro and in vivo techniques have the potential to contribute to the development of more direct methods for assessing protein folding in the cell, which is currently limited to indirect methods like disulfide bond formation, interactions with molecular chaperones, and further transport along the secretory pathway versus degradation. In addition to increasing our general understanding of ER quality control, our study will provide novel insights into the biosynthesis of TCR that will likely apply to other immunoreceptors and might provide novel ways to manipulate them therapeutically.

描述（由应用提供）：``T细胞受体对于自适应免疫系统的主要功能至关重要，并且是最复杂的细胞表面受体之一。它由八个必须在适当的化学计量中组装的八个多肽链组成，以执行其重要功能。因此，其组装为ER质量控制机械构成了一项艰巨的任务。尽管大量文献存在于“ TCR的组装和质量控制”上，但这些努力主要集中在单个链的异常跨膜领域。这些拥有的充电保留了，当不配对时，``TCR链的加速降解''，据信可以驱动组装。但是，尚未阐明该提出的“整体膜质量控制”步骤的基础。此外，很少关注该受体的流体部分的可能作用，这很可能是通过已知的ER质量控制机械仔细检查的区域。为了解决这种缺乏症，我们建议将生物物理和基于细胞的研究结合起来，以获取有关可以与细胞中检查点相关的高分辨率结构和动力学数据。我们从这些方法获得的初步数据已经揭示了TCR链的两个意外特征。我们发现，在没有与链的关联的情况下，它的恒定域是无组织的，并且单独表达时，其跨膜区域不会集成到ER膜中。这两个功能很可能在受体组件的质量控制中提供检查点。这些初步的见解将扩展，以获得ER机制的综合视图，该视图有助于和监测TCR生物合成，仅允许在细胞表面表达正确组装的受体。 公共卫生相关性：尽管识别ER质量控制机制的组成部分取得了很大进展，但执行它们的基本机制仍然知之甚少。对于控制多细胞生物中重要功能的跨膜蛋白尤其如此，并且通常是药物靶标。我们提出研究，以解读必需T细胞抗原受体（TCR）的组装和质量控制的新方面，这是已知的最复杂的细胞表面受体之一。我们之所以选择TCR，是因为已知严格的质量控制检查点可以仔细检查该八个链受体的组装，但是尚不清楚基本的分子机制。尚未对其流明领域在质量控制中的作用进行充分的研究，并且推定的“跨膜质量控制”步骤仍然是投票。我们提议的项目将解决两层质量控制层。从我们提出的体外和体内技术组合中获得的机理见解有可能有助于开发更直接的方法来评估细胞中蛋白质折叠的方法，该方法目前仅限于间接方法，例如二硫键键形成，例如与分子伴侣的相互作用，以及与秘书pathway pathway fors vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers vers。除了提高我们对ER质量控制的一般理解外，我们的研究还将提供有关TCR生物合成的新见解，这些见解可能适用于其他免疫受体，并可能提供新颖的方法来治疗它们。