Functional analyses of basement membrane components in association and dissociation of hemidesmosomal adhesion structures

在这笔资金的支持下，我们取得了以下成绩我们成功地分离了基底膜（BM）部分，并制备了一组针对基底膜成分的单克隆抗体。利用抗体，我们证明了腺肌上皮细胞具有上皮型半粒酶（HD）和平滑肌型粘附连接作为细胞-基质粘附装置。我们还发现层粘连蛋白γ - 2亚基的加工促进了基质中层粘连蛋白5的周转我们证明了BP180/ XVII型胶原的细胞外结构域的切割是由细胞表面的基质金属蛋白酶完成的，而不是在细胞内膜我们研究了单纯上皮中HD型黏附结构，发现结肠上皮细胞中除了表达BP180外，还有II型HD成分，包括粘附素和整合素α6β4，而尿小管上皮细胞中除了整合素α6β4外，没有HD成分的表达，提示存在新的黏附结构我们从兔平滑肌细胞中分离出一种180/200 kD的蛋白，鉴定其为哺乳动物synemin，一种中间纤维蛋白，并证明该蛋白在包括肌上皮细胞在内的所有四种肌肉细胞中均有表达，并与其他if蛋白如角蛋白和desmin相互作用。

Supported by this grant, we have obtained following achievements.1 We have succeeded in isolating a basement membrane (BM) fraction and prepared a panel of monoclonal antibodies to BM components. Using the antibodies we demonstrated that glandular myoepithelial cells have both the epithelial-type hemidesmosome (HD) and the smooth muscle-type adherens junction as cell-matrix adhesion apparatus. We also showed that processing of laminin γ2 subunit facilitates the turnover of laminin 5 in the matrix.2 We demonstrated that the cleavage of the extracellular domain of BP180/type XVII collagen is done by a matrix metalloproteinase on the cell surface, not in the intracellular membrane.3 We investigated HD-type adhesion structures in simple epithelia, and found an expression of BP180, in addition to type II HD-components consisting of plectin and integrin α6β4, in colon epithelial cells, and no HD component except integrin α6β4 in uriniferous tubular epithelial cells, suggesting the presence of novel adhesion structure.4 We isolated a 180/200 kD protein from rabbit smooth muscle cells and identified it as mammalian synemin, an intermediate filament protein, and demonstrated that this protein is expressed in all four types of muscle cells including myoepithelial cells, interacting with other IF-proteins such as keratin and desmin.