GLYCOPROTEIN HORMONE OLIGOSACCHARIDES

糖蛋白激素低聚糖

• 批准号: 3242600
• 负责人: JACQUES U BAENZIGER
• 金额: $ 31.64万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1994-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3242600
• 关键词: Golgi apparatus; carbohydrate biosynthesis; carbohydrate sequence; carbohydrate structure; chemical structure function; complementary DNA; enzyme mechanism; enzyme substrate; follicle stimulating hormone; glycoprotein structure; glycoproteins; glycosyltransferase; high performance liquid chromatography; hormone regulation /control mechanism; laboratory mouse; laboratory rabbit; luteinizing hormone; nucleic acid sequence; oligosaccharides; peptide hormone; peptide structure; protein sequence; site directed mutagenesis; sulfotransferase; thyrotropin

The glycoprotein hormones lutropin (LH), follitropin (FSH), thyrotropin (TSH), and chorionic gonadotropin (CG) are a family of four closely related dimeric proteins which share common alpha-subunits but have hormone-specific beta-subunits. LH bears Asn-linked oligosaccharides which terminate with the sequence SO4-4GalNAc beta 1,4GlcNAc beta 1, 2Man alpha whereas FSH, synthesized in the same cell, contains Sialic acid-Gal in place of SO4-GalNAc. The goals of this proposal are to characterize in depth the two transferases we have identified whose sequential action is responsible for synthesis of these sulfated oligosaccharides, and to determine the biologic function of these sulfated structures. To accomplish this we will purify the sulfo- and GalNAc-transferases, and define their kinetic and substrate recognition parameters. cDNAs coding for the sulfo- and GalNAc-transferases will be prepared and sequenced to establish the primary structures of these membrane-bound transferases. We will determine if they have regions which are homologous to other glycosyltransferases and Golgi proteins, and may account for their specificities and localization within the Golgi. We have shown that some aspect of the peptide sequence in glycoprotein hormones is recognized by the GalNAc-transferase. The amino acid sequence of this recognition marker will be identified. The possible presence of this marker and sulfated structures on other types of glycoproteins will be assessed. We will explore whether the expression of these transferases is under hormonal regulation and results in the synthesis of oligosaccharides with altered structures. The functional significance of these oligosaccharides for sorting of LH and FSH to different granules within the gonadotroph, for regulating hormone bioactivity, and for determining clearance from the blood will be examined. The properties of glycoproteins in other cells bearing the same structures will be compared with those of the hormones to determine if their oligosaccharides have related functions. The glycoprotein hormones provide a model system for understanding how unique oligosaccharides arise on select families of proteins. Since only specific members of the glycoprotein hormone family bear sulfated oligosaccharides, this is an important model system which will allow us to develop a better understanding of the biologic significance of glycosylation.

糖蛋白激素促黄体激素 (LH)、促卵泡激素 (FSH)、促甲状腺激素 (TSH) 和绒毛膜促性腺激素 (CG) 是密切相关的四个家族 二聚体蛋白质具有共同的 α 亚基，但具有 激素特异性β亚基。 LH 带有 Asn 连接的寡糖， 以序列 SO4-4GalNAc beta 1,4GlcNAc beta 1, 2Man alpha 终止 而在同一细胞中合成的 FSH 则含有唾液酸-Gal SO4-GalNAc 的位置。该提案的目标是描述 深度我们已经确定的两个转移酶，其顺序作用是 负责合成这些硫酸化寡糖，并 确定这些硫酸化结构的生物学功能。为了完成 我们将纯化磺基转移酶和 GalNAc 转移酶，并定义它们的 动力学和底物识别参数。编码磺基的 cDNA GalNAc 转移酶将被制备并测序以确定 这些膜结合转移酶的一级结构。我们将确定 如果它们具有与其他糖基转移酶同源的区域并且 高尔基体蛋白，并可能解释其特异性和定位 高尔基体内。我们已经证明肽序列的某些方面 糖蛋白激素被 GalNAc 转移酶识别。氨基 该识别标记的酸序列将被鉴定。可能的 该标记物和其他类型的硫酸化结构的存在 将评估糖蛋白。我们将探讨是否表达 这些转移酶受激素调节并导致 结构改变的寡糖的合成。功能性的 这些寡糖对于 LH 和 FSH 分类的重要性 促性腺激素内的不同颗粒，用于调节激素 将检查生物活性并确定血液清除率。 具有相同结构的其他细胞中糖蛋白的特性 将与激素进行比较以确定它们是否 寡糖具有相关功能。糖蛋白激素提供 用于了解独特寡糖如何产生的模型系统 选择蛋白质家族。由于只有特定成员 糖蛋白激素家族含有硫酸化寡糖，这是一种 重要的模型系统，这将使我们能够开发出更好的 了解糖基化的生物学意义。