BIOSYNTHESIS OF BRAIN CARBONIC ANHYDRASE

本项目旨在了解神经胶质细胞的组装， 质膜离子转运蛋白。 这些实验旨在 检查翻译和翻译后事件介导的 插入1）膜结合碳酸酐酶和2）两个血浆 与阳离子形成相关的膜蛋白脂亚基 进入神经胶质细胞膜。 的共翻译插入 这些蛋白质进入内质网（ER）将被分析， 利用分离自大鼠的膜结合多核糖体的无细胞系统 个脑袋 在实验中加入了适当的控制措施。 设计以帮助定义新生蛋白质与ER的特异性相互作用 膜的 将使用充分表征的 每种蛋白质的免疫吸附剂。 膜结合的肽段 碳酸酐酶，这是嵌入在膜，将被确定为 ER的翻译后蛋白水解和肽的鉴定 免疫吸附。 新生蛋白质中这种肽的性质 将与分离血浆中天然蛋白质中发现的蛋白质进行比较 膜的 翻译后的事件之间的干预， 翻译和插入到质膜的膜结合 碳酸酐酶将在组织切片中进行研究， 将在培养的神经胶质瘤细胞中研究质膜蛋白脂质。 这些单独的系统已经被有意地选择，以便优化 分析每种蛋白质。 高尔基体功能抑制剂，从头脂质 合成和微管功能将被用来帮助定义 这些细胞过程在这些蛋白质组装中的作用。 的 还将检查这些蛋白质被酰化的可能性。 我们 感受到膜结合碳酸酐酶和质膜 蛋白脂质是中枢神经系统中离子动力学的组成部分， 控制其组装的机制的阐明应该产生 关于控制大脑离子环境的因素的宝贵数据。 它 因此，可以合理地假设， 这项研究不仅有助于我们理解生物起源， 离子转运蛋白，但可能有助于 水肿和癫痫的病理生理状态。

This project is directed at an understanding of the assembly of glial plasma membrane ion transport proteins. The experiments are designed to examine the translational and post translational events mediating the insertion of 1) membrane-bound carbonic anhydrase and 2) the two plasma membrane proteolipid subunits associated with the formation of cation specific channels, into glial membranes. The cotranslational insertion of these proteins into the endoplasmic reticulum(ER) will be analyzed with cell free systems utilizing membrane-bound polysomes isolated from rat brain. Appropriate controls have been incorporated into the experimental design to help define specific interactions of nascent proteins with the ER membrane. Analyses will be carried out using well characterized immunoadsorbants for each protein. The peptide segment of membrane-bound carbonic anhydrase, that is imbedded in the membrane, will be identified by post- translational proteolysis of the ER and identification of the peptide by immune adsorption. The nature of this peptide in the nascent protein will be compared to that found in the native protein in isolated plasma membrane. The post translational events intervening between the translation and the insertion into plasma membrane of membrane-bound carbonic anhydrase will be studied in tissue slices while the assembly of the plasma membrane proteolipids will be studied in cultured glioma cells. These separate systems have been deliberately chosen so as to optimize the analyses of each protein. Inhibitors of golgi function, de novo lipid synthesis and microtubular function will be employed to help define the role of these cellular processes in the assembly of these proteins. The possibility that these proteins are acylated will also be examined. We feel that membrane-bound carbonic anhydrase and the plasma membrane proteolipids are integral to ion dynamics in the central nervous system and the elucidation of the mechanisms controlling their assembly should yield valuable data on the factors controlling the ionic milieu of the brain. It is therefore reasonable to assume that the basic information obtained in this study will not only contribute to our understanding of the biogenesis of ion transport proteins but to factors that could contribute to the pathophysiologic states of edema and epilepsy.