TRAFFIC OF IMMUNOGLOBULINS AND MHC PROTEINS IN B CELLS

B 细胞中免疫球蛋白和 MHC 蛋白的运输

• 批准号: 3145288
• 负责人: YAIR ARGON
• 金额: $ 15.03万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1993-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3145288
• 关键词: B lymphocyte; Golgi apparatus; binding proteins; endoplasmic reticulum; exo alpha sialidase; exocytosis; genetic strain; glycoprotein biosynthesis; immunocytochemistry; immunoelectron microscopy; immunoglobulin G; immunoglobulins; laboratory mouse; laboratory rat; leukocyte antigen typing; ligands; major histocompatibility complex; membrane activity; membrane permeability; mutant; phosphorylation; protein biosynthesis; protein signal sequence

This project will examine the intracellular transport of two glycoproteins, immunoglobulins (Ig) and MHC class I antigens, in murine B lymphocytes. Proper intracellular transport of these proteins to the plasma membrane is cricial for the functioning of B lymphocytes as Ig secretors and as antigen presenters. Two stages of transport are of special interest: 1. The transition between the Endoplasmic Reticulum (ER) and the Golgi complex. 2. The transition between the Golgi complex and the cell surface. Our main question about the ER-Golgi transition is identifying those structural features of IG lambda chains which are crucial for executing this rate-limiting step of transport. Such features may in fact serve as transport signals, for example by mediating interactions of lambda with other cellular proteins. To identify and map such structural features, we shall construct lambda transport mutants and ask that they satisfy two requirements: that they fail to exit the ER and that they fold properly. Such mutants can reasonably be interpreted as defective in transport signals. These mutants will then be used to examine the role of resident ER proteins, like Binding Protein, in retaining non-secreted Ig in the ER. Understanding the transition between the Golgi complex and the cell surface is important with respect to Beta cell function in antigen presentation, since this is a stage where endocytosed ligands and receptors mix with the exocytic traffic. We observed that the protonophore CCCP perturbs transport through this stage, in a compartment distal to the Golgi stack, which we think is the trans-Golgi reticulum. We propose to characterize this compartment further, by immuno-electron microscopy and histochemistry. Moreover, we propose to isolate the trans-Golgi reticulum and study its biochemical properties. Finally, the transport of MHC class I antigens between the Golgi complex and the cell surface will be studied, by examining the phosphorylation of these molecules and the relation between phosphorylation and the traffic to and from the cell surface.

该项目将检查两个糖蛋白的细胞内转运，即 鼠B淋巴细胞中的免疫球蛋白（IG）和MHC I类抗原。 这些蛋白质向质膜的适当细胞内转运为 B淋巴细胞作为Ig泌物和抗原的疾病 主持人。 两个运输的两个阶段是特别感兴趣的：1。 内质网（ER）和高尔基体配合物之间的过渡。 2。高尔基体配合物与细胞表面之间的过渡。 我们关于ER高尔基过渡的主要问题是确定这些问题 IG Lambda链的结构特征，对于执行至关重要 这种限制运输步骤。 这样的功能实际上可能是 运输信号，例如通过调解Lambda与 其他细胞蛋白。 为了识别和映射此类结构特征，我们 应构建Lambda运输突变体，并要求他们满足两个 要求：他们无法退出ER，并且折叠正确。 这样的突变体可以合理地解释为运输中有缺陷 信号。 然后，这些突变体将用于检查居民的作用 ER蛋白（例如结合蛋白）在ER中保留未分泌的Ig。 了解高尔基体配合物与细胞表面之间的过渡 对于抗原表现中的β细胞功能很重要， 由于这是一个阶段，内吞配体和受体与 外囊流量。 我们观察到protonophore cccp perturbs 穿过这个阶段，在距高尔基烟囱远端的隔间中运输， 我们认为这是跨性别的网状网。 我们建议表征 通过免疫电子显微镜和组织化学进一步，该隔室进一步。 此外，我们建议隔离反式高尔基网状并研究其 生化特性。 最后，MHC I类抗原的运输 在高尔基体配合物和细胞表面之间将通过 检查这些分子的磷酸化以及 磷酸化以及往返细胞表面的流量。