EPIDERMAL TRANSGLUTAMINASES

转谷氨酰胺酶在供体酰胺之间形成异肽交联物 由蛋白质结合的谷氨酰胺残基和受体epsilon-NH2组成 蛋白质结合的赖氨酸残基，从而形成不溶于水的 大分子蛋白质复合体。在表皮中，至少有三种酶 被认为是通过将某些定义的结构交联而起作用的 形成角化细胞膜的蛋白质，是转谷氨酰胺酶 1、2和3。我们正在详细研究这些酶。这个 角质形成细胞或包皮表皮中谷氨酰胺转氨酶1酶的表达 细胞是复杂的，因为它存在于多种可溶性和膜结合的环境中 全长以及蛋白质分解处理的形式。分区 胞质和细胞膜之间的差异是由不同的酰化作用控制的 肉豆蔻酸和棕榈酸酯。该酶广泛表达于 表皮和食道附件结构以及其他非上皮性结构 纸巾。同样，转谷氨酰胺酶3在许多组织中都有表达 其他非上皮性细胞类型。基因的近端启动子区域 谷氨酰胺转氨酶3基因位于谷氨酰胺转氨酶基因上方的前126个碱基内。 转录起始点，由Sp1基序组成，受 相邻的类ETS图案。这些都足以授予 上皮特异性表达。这个区域还含有一种钙 响应元素。每种化合物的晶体结构研究 目前正在进行三种酶的研究。

Transglutaminases form an isopeptide crosslink between an donor amide group of a protein-bound glutamine residue and a acceptor epsilon-NH2 of a protein-bound lysine residue, thereby forming an insoluble macromolecular protein complex. In the epidermis, at least three enzymes are thought to function by crosslinking certain defined structural proteins to form the cornified cell envelope, and are transglutaminases 1, 2 and 3. We are studying these enzymes in detail. The transglutaminase 1 enzyme in cultured keratinocytes or foreskin epidermal cells is complex, since it exists in multiple soluble and membrane-bound full-length as well as proteolytically-processed forms. The partitioning between the cytosol and membranes is controlled by differential acylation by myristate and palmitate. The enzyme is widely expressed in the epidermis and appendageal structures, as well as in other non-epithelial tissues. Similarly, the transglutaminase 3 enzyme is expressed in many other non-epithelial cell types. The proximal promoter region of the transglutaminase 3 gene is located within the first 126 bp above the transcription start site, and consists of an Sp1 motif modulated by adjacent ets-like motifs. These are sufficient to confer epithelial-specific expression. This region also contains a calcium responsive element. Crystallographic structural studies on each of the three enzymes are in progress.