RECEPTOR MEDIATED TRANSPORT OF GLYCOPROTEINS

受体介导的内吞作用是一种普遍现象，已被发现 与细胞器生物发生、激素和有丝分裂原生理学有关 大分子进入细胞的运输。肺泡巨噬细胞表达a 介导内吞和包装的甘露糖特异性受体 来自细胞外间隙的糖偶联物(包括溶酶体酶) 巨噬细胞的溶酶体。我已经发展出一种正式的动能 准确地描述了由其介导的稳态摄取机制 这种受体和发展起来的研究技术，用于研究 孤立的内吞过程。使用这些方法，我们已经能够 以表明内体酸化在稳定状态下是限速的 领悟。我建议研究内体酸化的机理。 使用甘露糖特异性配体的完整细胞和分离的内涵体 带有共价连接的荧光pH敏感发色团的受体。 囊泡运输的细胞内途径和机制将是 使用动力学和分馏技术进行了研究。标记配体和 标记受体(使用我开发的原位标记技术 受体)将用于跟踪这些组件的进程 通过受体介导的细胞内吞噬作用。这个 内吞泡酸化在溶酶体释放中的作用 酵母多糖、内毒素和佛波醇肉豆蔻酸刺激的酶 已评估。巨噬细胞对溶酶体水解酶的刺激分泌 将被用作巨噬细胞在慢性疾病中的作用的模型 发炎。分泌机制将被研究，并作用于 甘露糖特异性内吞作用在胞外水解酶调控中的作用 在这些条件下的水平将被确定。

Receptor mediated endocytosis is a general phenomena that has been found to be relevant to organelle biogenesis, hormone and mitogen physiology and the transport of macromolecules into cells. Alveolar macrophages express a mannose specific receptor that mediates the endodytosis and packaging of glycoconjugates (including lysosomal enzymes) from the extracellular space to the lysosomes of the macrophage. I have developed a formal kinetic mechanism which accurately describes the steady-state uptake mediated by this receptor and developed techniques for studying segments of the endocytic process in isolation. Using these approaches we have been able to show that endosome acidification is rate limiting during steady-state uptake. I proposed to study the mechanism of endosome acidification in intact cells and isolated endosomes using ligands specific for the mannose receptor with covalently attached fluorescent pH sensitive chromophores. The intracellular pathway and mechanism of vesicular transport will be studied using kinetic and fractionation techniques. Labelled ligand and labelled receptor (using a technique I have developed for in situ labelling of the receptor) will be used to follow the progression of these components through the intracellular pathway of receptor mediated endocytosis. The role of acidification of endocytic vesicles in the release of lysosomal enzymes stimulated by zymosan, endotoxin and phorbol myristic acid will be evaluated. The stimulated secretion of lysosomal hydrolases by macrophages will be used as a model for the role of macrophages in chronic inflammation. The mechanism of secretion will be studied and the role of mannose specific endocytosis in the regulation of extracellular hydrolase levels under these conditions will be determined.