EPIDERMAL TRANSGLUTAMINASES

转氨酶在受体酰胺之间形成异肽交联， 蛋白质结合的谷氨酰胺残基和蛋白质的供体e-NH 2的基团 结合赖氨酸残基，从而形成不溶性大分子蛋白质 复杂. 在表皮中，至少有三种酶被认为起作用 通过交联某些确定的结构蛋白质形成皮质醇， 细胞被膜，并且是转氨酶1、2和3。 我们正在研究 这些酶的细节。 通过使用一种新的特异性抗体，我们发现 培养的角质细胞或包皮中的转氨酶1 表皮细胞是非常复杂的，因为它存在于多种可溶性和 膜结合全长以及蛋白水解加工形式。 可溶相和膜相之间的分配由以下控制： 肉豆蔻酸酯和棕榈酸酯的差异酰化。 这种酶广泛用于 在表皮和附属器结构中表达，以及在其他组织中表达。 非上皮组织。 基因的近端启动子区 转氨酶3基因位于第一个126 bp以上， 转录起始位点，由Sp1基序组成， 相邻的类ETS基序。 这些足以使 上皮特异性表达。 该区域还含有钙 响应元件

Transglutaminases form an isopeptide crosslink between an acceptor amide group of a protein bound glutamine residue and a donor e-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. By use of a new specific antibody, we have found that the transglutaminase 1 enzyme in cultured keratinocytes or foreskin epidermal cells is very complex, since it exists in multiple soluble and membrane-bound full-length as well as proteolytically- processed forms. The partitioning between the soluble and membrane phases 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. 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.