CELLULAR ASSEMBLY AND TRANSPORT OF THE IGE RECEPTOR

IGE 受体的细胞组装和运输

• 批准号: 6624555
• 负责人: MICHAEL W ROBERTSON
• 金额: $ 31.03万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-12-15 至 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624555
• 关键词: antibody receptor; basophils; calnexin; endoplasmic reticulum; eosinophil; immunoglobulin E; intracellular transport; molecular chaperones; protein biosynthesis; protein transport; receptor expression; tissue /cell culture

DESCRIPTION (investigator's abstract): It is well established that the initiating requirement of the allergic response involves the interaction of IgE with its high affinity receptor (FceRI) expressed on hematopoietic cells. Efforts to modulate this interaction through manipulation of the expression levels of either IgE or cell surface FcERI would offer the potential to intervene in the pathogenesis of the allergic response. The intracellular assembly and transport of FcERI to the plasma membrane is a complex process that has thus far been largely unexplored. Definition of critical steps in the assembly and transport pathway could open new possibilities in blocking FcERI expression with the broader aim of attenuating the allergic response. We will initially explore the assembly and transport characteristics of the human FceRI alphagamma2 receptor. In addition to association of the FceRI gamma-chain, two other critical events occur during FceRI ct-chain biosynthesis that profoundly influence the formation of a transport competent ag2 receptor: (i) glycosidase-mediated processing of a-chain core oligosaccharides in the ER and; (ii) the association of specific ER chaperones, such as calnexin, with the nascent FceRI a-chain. We will focus on the role of calnexin in promoting ag2 assembly and cell surface expression which, based on preliminary results, appears to exert a profound effect on the level of cell surface expression. These studies will then be extended to expression of transfected tetrameric FceRI abg2 receptor, as well as constitutive receptor in eosinophils and basophils. FceRI abg2 may exhibit an intrinsically higher expression phenotype than the ag2 receptor, possibly derived from improved, beta-chain-dependent intracellular assembly, stability and transport properties mediated by specific ER chaperones. Initial studies have revealed that calnexin associates with the FceRI a subunit, an association predicted to occur exclusively via the N-linked glycans found in the ct-chain ectodomain. A further goal of this proposal is compare and defined the role of each of the 7 N-linked glycosylation sites in association with calnexin and other ER chaperone and their effect on cell surface expression. A final objective in this program is the further analysis of intracellular transport characteristics of a truncated FceRI a-chain, lacking only the cytoplasmic domain sequence, which expresses at a high level on the surface of transfected cells in the absence of the y-chain. Thus we will, for the first time, determine g-chain independent a-chain-specific transport and ER quality control characteristics.

描述（研究者的摘要）： 众所周知， 过敏反应的启动需要涉及 IgE 的相互作用 其高亲和力受体 (FceRI) 在造血细胞上表达。 通过操纵表达来调节这种相互作用的努力 IgE 或细胞表面 FcERI 的水平将提供潜力 干预过敏反应的发病机制。细胞内的 FcERI 的组装和运输到质膜是一个复杂的过程 迄今为止，这在很大程度上尚未被探索。关键步骤的定义 组装和运输途径可能为阻断 FcERI 开辟新的可能性 表达的更广泛目标是减轻过敏反应。我们将 初步探索人FceRI的组装和运输特性 αγ2受体。除了 FceRI 伽玛链的关联之外，两个 FceRI ct 链生物合成过程中发生的其他关键事件对 影响具有运输能力的 AG2 受体的形成：(i) ER 中糖苷酶介导的 a 链核心寡糖加工； (ii) 特定 ER 伴侣（例如钙联蛋白）与 新生的 FceRI a 链。我们将重点关注calnexin对ag2的促进作用 组装和细胞表面表达，根据初步结果， 似乎对细胞表面表达水平产生深远的影响。 这些研究随后将扩展到转染四聚体的表达 FceRI abg2 受体，以及嗜酸性粒细胞和 嗜碱性粒细胞。 FceRI abg2 可能表现出本质上更高的表达表型 比ag2受体，可能源自改进的β链依赖性 特定介导的细胞内组装、稳定性和运输特性 急诊室监护人。初步研究表明，钙连接蛋白与 FceRI 亚基，预计仅通过 N 连接发生的关联 ct 链胞外域中发现的聚糖。该提案的另一个目标是 比较并定义了 7 个 N 连接糖基化位点中每一个的作用 与钙联蛋白和其他 ER 伴侣的关联及其对细胞的影响 表面表达。该计划的最终目标是进一步分析 截短的 FceRI a 链的细胞内运输特性， 仅缺少高水平表达的细胞质结构域序列 在没有 y 链的情况下，位于转染细胞的表面。因此我们 将首次确定g链独立于a链特定 运输和 ER 质量控制特性。