DESMOSOMAL PROTEINS AND THE CELL

桥粒蛋白和细胞

• 批准号: 2184851
• 负责人: PAMELA COWIN
• 金额: $ 23.86万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2184851
• 关键词: DESMOSOMAL; PROTEINS; CELL

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.

桥粒芯糖蛋白和桥粒胶蛋白是主要的粘合剂成分 桥粒并形成钙粘蛋白超家族的两个不同亚型 细胞间粘附和形态调节蛋白。粘合性能 这些和其他钙粘蛋白型蛋白的细胞骨架连接是 通过它们与几种细胞质蛋白的结合来调节。 斑珠蛋白与桥粒芯糖蛋白和桥粒胶蛋白有物理联系 在桥粒以及经典钙粘蛋白，集中在 粘附连接。作为与所有三个交互的唯一组件 斑珠蛋白是上皮细胞的主要细胞间粘附蛋白 独特的定位在协调粘合剂方面发挥关键作用 细胞的特性。斑珠蛋白也是结构和功能 参与果蝇细胞命运决定的蛋白质的同源物 并已被证明参与 PC12 细胞的 Wnt-1 转化。 此外，斑珠蛋白最近已被证明可以形成胞质 与另一种结构相关的蛋白质 APC 形成复合物，APC 是 与遗传性结肠癌相关的基因。这个家庭的 因此，蛋白质可能被认为是细胞间粘附的核心参与者 和肿瘤抑制。鉴于斑珠蛋白参与 上面概述的重要细胞过程我建议进一步 研究该蛋白质及其受体的作用。我的具体目标 是： 1. 考察对细胞粘附和增殖的影响 过度表达斑珠蛋白的天然形式和突变形式。这些突变体是 旨在饱和钙粘蛋白或 APC 上的特异性结合位点 增强或消除这些蛋白质与 细胞骨架。 2. 确定桥粒芯糖蛋白/斑珠蛋白的额外相互作用 复合物：a) 纯化并克隆 plakoglobin 的 70 kDa 细胞质伴侣 b) 鉴定与细胞质结构域结合的新伙伴 通过筛选文库，将桥粒芯糖蛋白表达为融合蛋白 相同的融合蛋白并采用酵母双杂交系统。 3) 表征桥粒钙粘蛋白受体及其功能 使用碱性磷酸酶干扰桥粒形成 桥粒芯糖蛋白标记的可溶性胞外域。