DESMOSOMAL PROTEINS AND THE CELL

桥粒粘连蛋白和桥粒粘连蛋白是主要的粘连成分 桥粒，形成钙粘蛋白超家族的两个不同亚型 细胞间黏附和形态调节蛋白。胶粘剂的性能 这些和其他钙粘附素类型蛋白的细胞骨架连接是 受它们与几种细胞质蛋白结合的调节。 蛋白与桥粒和桥粒粘连蛋白在物理上都有联系。 在桥粒和经典钙粘素中也是如此，经典钙粘附素集中在 粘连结合部。作为唯一可以与所有三个组件交互的组件 上皮细胞的主要细胞-细胞黏附蛋白，即白蛋白 独特的定位，在协调粘合剂方面发挥关键作用 单元格的属性。白蛋白还具有结构和功能。 果蝇细胞命运决定蛋白的同源物 并参与了WNT-L对PC12细胞的转化。 此外，最近发现白蛋白形成胞浆。 与另一种结构上相关的蛋白质APC的复合体，APC是 一种与遗传性结肠癌相关的基因。这个家庭 因此，蛋白质可能被认为是细胞间黏附的中心角色。 和肿瘤抑制。鉴于白蛋白参与了 上面概述的重要细胞过程我建议进一步 研究这种蛋白质及其受体的作用。我的具体目标 包括： 1.检测银杏叶提取物对细胞黏附和增殖的影响 过度表达天然和突变形式的蛋白。这些突变体是 旨在饱和钙粘素或APC和钙粘蛋白上的特定结合位点 来加强或否定这些蛋白质与 细胞骨架。 2.确定桥粒糖蛋白/白蛋白的额外相互作用 复合体：a)纯化和克隆70 kDa蛋白胞浆配对蛋白 B)确定与胞质结构域结合的新伙伴 桥粒芯糖蛋白在文库筛选中的融合表达 相同的融合蛋白，并采用酵母双杂交系统。 3)桥粒钙粘附素受体的特征和功能 利用碱性磷酸酶干扰桥粒的形成 桥粒芯糖蛋白的标记可溶性胞外结构域。

Desmogleins and desmocollins are the major adhesive components of desmosomes and form two distinct subtypes of the cadherin superfamily of cell-cell adhesion and morphoregulatory proteins. The adhesive properties and cytoskeletal connections of these and other cadherin-type proteins are modulated by their association with several cytoplasmic proteins. Plakoglobin physically associates with both desmogleins and desmocollins at the desmosome as well as with classical cadherins which concentrate in the adherens junction. As the only component to interact with all three of the major cell-cell adhesive proteins of epithelia, plakoglobin is uniquely positioned to play a key role in co-ordinating the adhesive properties of the cell. Plakoglobin is also the structural and functional homologue of a protein involved in cell fate determination in Drosophila and has been shown to participate in Wnt-l transformation of PC12 cells. Furthermore plakoglobin has recently been shown to form cytosolic complexes with another structurally related protein, APC, the product of a gene linked to an inherited form of colon cancer. This family of proteins may therefore be considered central players in cell-cell adhesion and tumor suppression. Given the involvement of plakoglobin in the important cellular processes outlined above I propose to further investigate the role of this protein and its receptors. My specific aims are: 1. To examine the effect on cell adhesion and proliferation of overexpressing native and mutant forms of plakoglobin. These mutants are designed to saturate specifically binding sites on cadherins , or, APC and to potentate or negate the interactions of these proteins with the cytoskeleton. 2. To identify the additional interactions of desmoglein/plakoglobin complexes: a) purify and clone a 70 kDa cytoplasmic partner of plakoglobin b) identify the novel partners binding to the cytoplasmic domain of desmoglein expressed as a fusion protein by screening libraries with the same fusion protein and employing the yeast two-hybrid system. 3) To characterize desmosomal cadherin receptors and functionally interfere with desmosome formation by use of an alkaline phosphatase tagged soluble ectodomain of desmoglein.