Functional Significance of Protein Deimination during the Cornification of Epidermis

我们之前曾报道在大鼠的表皮中存在去亚胺角蛋白和丝状微丝蛋白(J.Invest。皮姆托尔。105,163-69(1995年)；助学金资助06833012)。在这里，我们进行了主要的脱亚胺基角蛋白分子的鉴定和肽基精氨酸脱亚胺酶(PAD)的cDNAs的克隆。我们还利用不同的实验系统进行了蛋白质脱胺的比较研究。人和小鼠表皮中的主要脱胺蛋白是角化层中部分降解和二硫键交联的角蛋白K1，这表明脱胺蛋白可能在调节K1与其伙伴角蛋白K10、已存在的角蛋白K5/K14网络或角蛋白相关蛋白的相互作用中发挥作用。从经维甲酸诱导表达PAD的永生化新生大鼠角质形成细胞的cDNA文库中分离到3个PAD克隆。其中一个与本实验室以前获得的骨骼肌PAD基因非常相似。另外两个似乎是新的编码垫的cDNA。进一步的研究正在进行中，以确定它们中的任何一个是否编码在表皮中表达的PAD。在出生后的几个小时内，小鼠表皮中角蛋白和丝状微丝蛋白的去除量显著增加。对胎儿期晚期胚胎皮肤的培养表明，这些表皮蛋白的正常去除需要暴露在空气中。使用人、大鼠、小鼠和猪的比较研究表明，细丝蛋白脱亚胺的物种差异显著。

We previously reported the presence of deiminated keratins and filaggrin in rat epidermis (J.Invest. Dermtol. 105,163-69 (1995) ; supported by Grant-in-Aide 06833012). Here we performed identification of the major deiminated keratin molecule and cloning of peptidylarginine deiminase (PAD) cDNAs. We also conducted comparative studies of protein deimination using various experimental systems.1. Major deiminated proteins in human and mouse epidermis were identified to be partially degraded and disulfide-cross-linked keratin K1 in the cornified layr suggesting the possible role of protein deimination in modulating the interaction of K1 with its partner keratin K10, pre-existent keratins K5/K14 network or keratin-associated proteins.2. Three PAD clones were isolated from a cDNA library of immortalized newbom rat kerationcytes that had been induced to express PAD with retinoic acid. One of them closely resembled skeletal muscle PAD cDNA previously obtained in our laboratory. The other two appeared to be novel cDNAs encoding PADs. Further research is in progress to see if either of them encodes PAD expressed in the epidermis.3. Deimination of keratins and filaggrin in mouse epidermis was found to increase markedly during postnatal few hours. Cultivation of late prenatal embryonic skin suggested that exposure to air is required for normal deimination of these epidermal proteins. Comparative studies using human, rat, mouse, and guine a pig showed significant species differences in filaggrin deimination.