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GLYCOPROTEIN HORMONE OLIGOSACCHARIDES

糖蛋白激素低聚糖

基本信息

批准号：
7900865
负责人：
JACQUES U BAENZIGER
金额：
$ 57.8万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-27 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7900865
关键词：
Ablation Accounting Alzheimer&apos s Disease Amino Acid Sequence Amino Acids Area Asialoglycoprotein Receptor Bacteriophages Behavior Biochemical Genetics Biological Biological Assay Blood Brain Breast Carbohydrates Complex Development Estrogens Family Family member Fertility Galactosides Genes Genetic Glycoproteins Gonadal Steroid Hormones Grant Half-Life Hormonal Hormone Receptor Hormones In Vitro Infertility Inorganic Sulfates Kidney Libraries Link Location Luteinizing Hormone Malignant Neoplasms Malignant neoplasm of prostate Mannose Mediating Metabolic Clearance Rate Mus Oligosaccharides Pattern Peptides Pituitary Gland Play Production Progesterone Property Protein Region Proteins Regulation Reproduction Reproductive Behavior Reproductive Biology Role Salivary Glands Sexual Development Sialic Acids Sialyltransferases Structure Structure-Activity Relationship System Testosterone Thyroid Function Tests Thyrotropin Time Tissues Transferase Unspecified or Sulfate Ion Sulfates Ursidae Family carbohydrate structure family structure glycosylation hormone regulation hypothalamic pituitary gonadal axis in vivo malignant breast neoplasm member novel protein aminoacid sequence protein structure receptor sulfotransferase tool

项目摘要

The long term objective of this grant is to define the biological significance of a family of unique N-linked carbohydrate structures that contain the sequence GalNAc beta1,4GlcNAc beta1,2Manα-, rather than the sequence Gal beta1,4GlcNAc beta1,2Manα- that is found on many glycoproteins. The beta1,4-N-acetylgalactosaminyl-transferases ( betaGTs) that add GalNAc to this structure are protein-selective, recognizing specific amino acid sequences in the distinctive set of glycoproteins that become modified. When present in the substrate protein, the recognition sequences can increase the catalytic efficiency of GalNAc transfer to a carbohydrate acceptor 500 fold. The terminal GalNAc can remain unmodified or be substituted with SO4 to form terminal SO4-4-GalNAc or with Sialic acid (Sia) to form Siaα2,6GalNAc. We have shown that glycoproteins such as luteinizing hormone (LH) that bear SO4-4-GalNAc are removed from the blood by the Mannose/GalNAc-4-SO4-receptor while those bearing either GalNAc or Siaα2,6GalNAc are removed by the asialoglycoprotein-receptor. Using genetic strategies to alter the structure of the carbohydrates on LH, we have demonstrated that the precise structure of the carbohydrates determine the LH concentration in the blood and the amount of estrogen and testosterone that are produced. As a result sexual development and reproductive behavior are altered. We will characterize the recognition determinant in glycoprotein substrates that is utilized by the betaGTs via a novel new assay system that allows us to determine the efficiency of GalNAc addition both in vivo and in vitro. We will also examine how different domains or regions of the protein-selective betaGTs contribute to the selective addition of GalNAc to LH and other glycoproteins. Members of the family of GalNAc containing structures that we have characterized on LH and other pituitary glycoproteins are also found on glycoproteins produced in the brain, kidney, salivary glands, and other tissues. We will define the impact of genetic ablation of the GalNAc-4- sulfotransferases and the protein-selective betaGTs on LH function. Since we have shown that ablation of GalNAc-4-sulfotransferase has effect on reproduction, we expect that ablating one or both of the betaGTs that are protein-selective will have an even greater effect and reveal additional functions for these carbohydrates. We will also define regulation of the expression of the transferases that mediate the synthesis of this family of structures. Their expression may change over the course of the hormonal cycle and at specific times during sexual development such as when sexual maturity is attained. We have clearly shown that changing the structures of the carbohydrates on LH has a significant impact on its in vivo function. We have demonstrated that the pattern of glycosylation is modulated in vivo. This is one of the first instances in which modulation of carbohydrate structures has been shown to have an impact in vivo. Defining precisely how this is regulated is critical for understanding reproductive biology and for understanding the role of glycosylation in modulating the properties of a wide range of glycoproteins such as hormones, receptors, and matrix components.

这项资助的长期目标是定义一个独特的 N 连锁家族的生物学意义碳水化合物结构包含序列 GalNAc beta1,4GlcNAc beta1,2Manα-，而不是序列 Gal beta1,4GlcNAc beta1,2Manα- 存在于许多糖蛋白上。 β1,4-N-乙酰半乳糖氨基转移酶将 GalNAc 添加到该结构中的 ( betaGT) 具有蛋白质选择性，可识别其中的特定氨基酸序列一组独特的被修饰的糖蛋白。当存在于底物蛋白中时，识别序列可以提高 GalNAc 转移至碳水化合物受体的催化效率 500 折叠。末端 GalNAc 可以保持未修饰或被 SO4 取代以形成末端 SO4-4-GalNAc 或与唾液酸（Sia）形成Siaα2,6GalNAc。我们已经证明糖蛋白如黄体生成素带有 SO4-4-GalNAc 的 (LH) 会被甘露糖/GalNAc-4-SO4-受体从血液中去除，而那些带有 GalNAc 或 Siaα2,6GalNAc 的载体被脱唾液酸糖蛋白受体去除。利用遗传改变 LH 上碳水化合物结构的策略，我们已经证明了碳水化合物决定血液中 LH 浓度以及雌激素和睾酮的含量所产生的。结果，性发育和生殖行为发生改变。我们将通过一种新的方法表征 betaGT 使用的糖蛋白底物中的识别决定簇分析系统使我们能够确定体内和体外添加 GalNAc 的效率。我们将还检查蛋白质选择性 betaGT 的不同结构域或区域如何促进选择性将 GalNAc 添加到 LH 和其他糖蛋白中。 GalNAc 家族的成员含有以下结构我们已经对 LH 进行了表征，并且在垂体产生的糖蛋白上也发现了其他垂体糖蛋白。脑、肾、唾液腺和其他组织。我们将定义 GalNAc-4- 基因消融的影响磺基转移酶和蛋白质选择性 betaGT 对 LH 功能的影响。既然我们已经证明了消融 GalNAc-4-磺基转移酶对繁殖有影响，我们预计消除一个或两个βGT 蛋白质选择性将产生更大的影响，并揭示这些碳水化合物的附加功能。我们还将定义介导该家族合成的转移酶表达的调节结构。它们的表达可能会在荷尔蒙周期的过程中以及在特定时间发生变化性发育，例如达到性成熟时。我们已经清楚地表明，改变 LH上碳水化合物的结构对其体内功能有显着影响。我们已经证明了糖基化模式在体内受到调节。这是调制的第一个实例之一碳水化合物结构已被证明对体内有影响。准确定义如何监管是对于理解生殖生物学和理解糖基化在调节生殖细胞中的作用至关重要多种糖蛋白的特性，例如激素、受体和基质成分。