RECOGNITION AND SORTING OF GLYCOPROTEINS

真核细胞具有识别、分类和运输的机制 胞外和胞内细胞器之间的跨膜蛋白 小路。除了少数例外，人们对它的特性知之甚少 在这一过程中被识别的单个蛋白质。在 应用实验的目的是：(1)定位两个字符的特征 嵌合糖蛋白，HAG和HAgC，负责指导 这些蛋白质进入内吞途径；(2)通过 HAgC靶向溶酶体，而HAg不靶向；(3)确定 HAG和HAgC的特征是否规定了其内化 还允许它们结合到网状蛋白涂层的成分上；(4)检查 外源跨膜和胞质结构域对结构的影响 ；(5)确定HA跨膜和 细胞质结构域影响HA正确定位的效率 分选至极化上皮细胞的顶面。一系列 嵌合基因将用寡核苷酸指导构建 诱变。这些基因将在SV40和牛乳头状瘤中表达 病毒载体。由这些基因编码的蛋白质将被分析 (I)转运到细胞表面的速率；(Ii)内化速率； (Iii)HA外区的形状、稳定性和功能的变化。 其中某些基因将在极化的上皮细胞中表达， 将研究改变的HA蛋白的分类。这些实验 将有助于理解分子机制 控制细胞表面蛋白的运输和分选。

Eukaryotic cells have mechanisms to recognize, sort, and transport transmembrane proteins between organelles of the exocytic and endocytic pathways. With few exceptions, little is known of the features of individual proteins that are recognized during this process. In the application experiments are proposed to: (1) locate the features of two chimeric glycoproteins, HAG and HAgC, that are responsible for directing these proteins into the endocytic pathway; (2) examine the mechanism by which HAgC is targeted to lysosomes whereas HAG is not; (3) determine whether the feature of HAG and HAgC that specifies their internalization also allows them to bind to components of clathrin coats; (4) examine the influence of foreign transmembrane and cytoplasmic domains on the structure of the HA external domain; (5) determine whether the HA transmembrane and cytoplasmic domains influence the efficiency with which HA is correctly sorted to the apical surface of polarized epithelial cells. A series of chimeric genes will be constructed using oligonucleotide directed mutagenesis. These genes will be expressed from SV40 and bovine papilloma virus vectors. The proteins encoded by these genes will be analysed for (i) rate of transport to the cell surface; (ii) rate of internalization; (iii) change in shape, stability, and function of the HA external domain. Certain of these genes will be expressed in polarized epithelial cells and sorting of altered HA proteins will be investigated. These experiments will contribute towards an understanding of the molecular mechanisms controling transport and sorting of cell surface proteins.