LATERAL ORGANIZATION OF EPITHELIAL CELL SURFACES

上皮细胞，占身体所有细胞的50%[和 占所有人类癌症的90%]具有定义功能， 创造和维持身体的生理区室。 它们在功能和形态上都是两极分化的， 执行这个功能。 脂质锚定蛋白，GPI=蛋白质和 鞘糖脂集中在大多数神经元的顶面， 极化上皮细胞 我们建议使用生物物理学 技术来研究的形成，和组织的排序 高尔基体和质膜中GPI蛋白的单位， 比较MDCK细胞中的分选单位，其中GPI蛋白被 直接递送至顶端表面，并且在WIF-B肝细胞中， 其中顶端蛋白质采取间接途径到达顶端 面 我们还将比较不同的横向组织 MDCK细胞和脂质体中的GPI蛋白。 以下问题 将解决：1）如何GPI蛋白和GSL浓缩， 与高尔基体中的其他蛋白质分离 2)什么是Cell & GPI-蛋白的聚簇和极性的蛋白特异性 在完全培养基中生长的细胞中， 缺乏LDL？ 我们解决这些问题的技术包括 荧光光漂白和恢复，FPR， 光漂白、FLIP和成像荧光共振能量 转移，FRET。

Epithelial cells, which comprise 50% of all cells in the body [and account for 90% of all human cancers] have as a defining function the creation and maintenance of physiological compartments of the body. They are functionally and morphologically polarized in order to perform this function. Lipid-anchored proteins, GPI=proteins and glycosphingolipids are concentrated at the apical surfaces of most polarized epithelial cells. We propose to use biophysical techniques to study the formation, and organization of the sorting units for GPI-proteins in the Golgi and plasma membranes and to compare the sorting units in MDCK cells, in which GPI-proteins are delivered directly to the apical surface, and in WIF-B hepatocytes, in which apical proteins take an indirect route to the apical surface. We will also compare the lateral organization of different GPI-proteins in MDCK cells and in liposomes. The following questions will be address: 1) How are GPI-proteins and GSL concentrated and segregated from other proteins in the Golgi? 2) What are the cell & protein specificities of the clustering and polarity of GPI-proteins in cells grown in complete medium and abolish their polarity in cells deprived of LDL? Our techniques to address these questions include fluorescence photo bleaching and recovery, FPR, fluorescence loss in photo bleaching, FLIP, and imaging fluorescence resonance energy transfer, FRET.