GOLGI COMPLEX COMPOSITION IN POLARIZED EPITHELIAL CELLS

Glgi复合物的功能将在两个极化中进行研究。 上皮细胞系 细胞系（MDCK和WIF-B）代表 两种上皮细胞（肾小管和肝细胞）的模型， 用于蛋白质和脂质分选的不同机制和/或位点， 递送至专门的质膜域。 高尔基复合体 在这个过程中扮演着重要的角色。 分选故障 极化上皮细胞中的机械有可能导致 疾病，因为这些细胞的完整性需要定义和 维持生物体内的生理区室。 理解 高尔基复合体在指导蛋白质和脂质的作用， 功能部位有助于了解疾病 过程 高尔基复合体由至少三个亚室组成： 堆叠，两侧各有两个多形性隔室，顺式 高尔基体网络（CGN）和反高尔基体网络（TGN）。 的 脂质双层对高尔基体结构和功能的贡献 将研究MDCK和WIF-B细胞。 分布、结构 和不寻常的磷脂半溶血双磷脂的生物合成 酸（在CGN和TGN中富集）将被确定， 函数将使用扰动来解决。 的 高尔基体亚室的鞘糖脂和胆固醇含量 控制单元和各种扰动后的单元将 确定，因为这些脂质已被假定有一个作用， 在上皮细胞中分选。 此外，由于肝细胞 据信缺乏一个直接的途径来传递新合成的 蛋白质从高尔基体到顶端质膜，这一途径， 新合成的鞘脂被输送到顶端 将研究血浆WIF-B细胞。 磷脂酰肌醇 对高尔基体的功能很重要， 不同于经典的信号转导途径。 有缺陷的 位于高尔基体的磷脂酰肌醇4，5-二磷酸5-磷酸酶 膜最近被牵连在眼脑肾综合征 其中极化细胞的子集是功能障碍的。 高尔基体脂质组成（包括磷脂酰肌醇4，5- 二磷酸）和MDCK细胞中潜在的蛋白分选缺陷 将评估缺乏5-磷酸酶。

The function of the Glgi complex will be studied in two polarized epithelial cell lines. The cell lines (MDCK and WIF-B) represent models of two epithelia (kidney tubule and hepatocyte) that use a different mechanism and/or site for protein and lipid sorting for delivery to specialized plasma membrane domains. The golgi complex plays an important role in this process. Malfunction of the sorting machinery in polarized epithelial cells has the potential to cause disease, since the integrity of these cells is required to define and maintain physiological compartments in the organism. Understanding the role of the Golgi complex in directing proteins and lipids their site of function is instrumental to understanding the disease process. The Golgi complex consists of at least three subcompartments: the stacks, and two pleomorphic compartments on either side, the cis Golgi network (CGN) and the trans Golgi network (TGN). The contribution of the lipid bilayer to Golgi structure and function in MDCK and WIF-B cells will be investigate. Distribution, structure and biosynthesis of the unusual phospholipid semilysobisphosphatidc acid (enriched in the CGN and TGN) will be determined, and its function will be addressed using perturbations. The glycosphingolipid and cholesterol content of Golgi subcompartments in control cells and in cells after various perturbations will be determined, since these lipids have been postulated to have a role in sorting in epithelial cells. In addition, since hepatocytes are believed to lack a direct pathway for delivery of newly synthesized proteins from the Golgi to the apical plasma membrane, the pathway by which newly synthesized sphingolipids are delivered to the apical plasma WIF-B cells will be investigated. The phosphatidylinositols are important for Golgi function in a role that is apparently distinct fromclassic signal transduction pathways. A defective phsphatidylinositol 4,5-bisphosphate 5-phosphatase localized to Golgi membranes was recently implicated in the oculocerebrorenal syndrome of Lowe, in which a subset of polarized cells is disfunctional. Golgi lipid composition (including phosphatidylinositol 4,5- bisphosphate) and potential protein sorting defects in MDCK cells lacking the 5-phosphatase will be assessed.