EXPRESSION, STRUCTURE AND FUNCTION OF THE CORNIFIED CELL ENVELOPE

皮质细胞被膜是一层多组分的15 nm厚的 沉积在血浆内表面的高度不溶性蛋白质 终末分化上皮细胞的膜。 的不溶性 在很大程度上是由于蛋白质的交联， 转氨酶 我们已经详细研究了其中两种蛋白质， 兜甲蛋白和小脯氨酸丰富（SPR）家族。 我们已经表示 在细菌中的人兜甲蛋白，并用它来表征其结构， 生物化学性质，以及表皮转氨酶的交联， 体外 类似地，我们在细菌中表达了几种SPR蛋白， 表征了它们的生物化学和体外交联特性。 结构研究正在进行中。 我们有特点的 SPR1和SPR2蛋白在小鼠中的差异表达特性 表皮和上皮组织。 我们用可控的蛋白水解 切开包皮内形成的表皮皮质细胞包膜 表皮在体内和角质形成细胞培养物在体外。 通过碱性 在甲醇中水解以除去共价结合的神经酰胺脂质 在此之前，我们已经能够探索这一问题的最深层次。 结构，对应于其组装的初始阶段。 我们的数据 这表明组装起始于角蛋白丝和 许多蛋白质遇到桥粒。

The cornified cell envelope is a multi-component 15 nm thick layer of highly insoluble protein deposited on the inner surface of the plasma membrane of terminally differentiating epithelial cells. The insolubility is due in large part to the crosslinking of the proteins by transglutaminases. We have studied two of the proteins in detail, loricrin and the small proline rich (SPR) families. We have expressed human loricrin in bacteria and used it to characterize its structure, biochemical properties, and crosslinking by epidermal transglutaminases in vitro. Similarly, we have expressed in bacteria several SPR proteins and characterized their biochemical and crosslinking properties in vitro. Structural studies are in progress. We have characterized the differential expression properties of the SPR1 and SPR2 proteins in mouse epidermis and epithelial tissues. We have used controlled proteolysis to dissect apart the epidermal cornified cell envelope formed in foreskin epidermis in vivo and in keratinocyte cultures in vitro. By alkaline hydrolysis in methanol to remove covalently bound ceramide lipids of the former, we have been able to explore the innermost aspects of this structure, corresponding to the initial stages of its assembly. Our data suggest that assembly is initiated at the site where keratin filaments and many proteins meet desmosomes.