Post-Translation Processing of Alpha-Dystroglycan

α-肌营养不良聚糖的翻译后加工

• 批准号: 7691724
• 负责人: DAVID H LIVE
• 金额: $ 16.23万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-22 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7691724
• 关键词: Acetylglucosamine; Address; Biochemical; Biochemical Reaction; Biological Assay; Carbohydrates; Clinical; Complement; Complex; Defect; Detection; Development; Disease; Dystroglycan; Dystrophin; Enzymes; Evaluation; Extracellular Matrix; Glycopeptides; Glycoproteins; Goals; Inherited; Intervention; Length; Link; Mannose; Maps; Mass Spectrum Analysis; Methods; Modification; Molecular; Mucins; Muscle Cells; Muscle eye brain disease; Muscular Dystrophies; Pattern; Physiological; Polypeptide N-acetylgalactosaminyltransferase; Polysaccharides; Post-Translational Protein Processing; Process; Property; Proteins; Research; Role; Series; Site; Sorting - Cell Movement; Specificity; Staging; Structure; Structure-Activity Relationship; Therapeutic; Therapeutic Intervention; Tissues; Touch sensation; Translation Process; Up-Regulation; Vertebral column; Vision; alpha Dystroglycan; base; chemical synthesis; congenital muscular dystrophy; design; dystroglycan 1; enzyme activity; enzyme substrate; gene therapy; glycosylation; glycosyltransferase; improved; insight; interest; intermolecular interaction; novel; polypeptide; protein O-mannose beta-1,2-N-acetylglucosaminyltransferase; public health relevance; therapy design; tool

DESCRIPTION (provided by applicant): The objective of the proposed research is to understand the post-translational processing of 1- dystroglycan (1-DG), a glycoprotein that is a key component of the dystrophin-glycoprotein complex, anchoring muscle cells to the extracellular matrix. Defective glycosylation of 1-DG in its highly conserved central mucin-like region, with numerous glycosylated S and T residues is the cause of several forms of hereditary muscular dystrophy. Pendant glycans are linked to the protein by either N-acetylglucosamine (GalNAc) or the more unusual mannose (Man) residue whose sites are now just being mapped. Relationships between problems in assembly of the O-Man tetra-saccharide and disease have been established. We have recently found evidence that the GalNAc residues are important structurally. Synthetic, biochemical and structural methods will be integrated in the research to develop an understanding of the steps in this complex process, providing a quantitative description of enzymatic transformations and also facilitating insights into key interactions in which 1-DG participates. An understanding of the steps in this process will provide basis for rational design of therapies to correct the defects, including gene therapy and up-regulation of other enzymes that may complement the defective ones. The focus will be on two steps following the initial O-Man modifications of 1-DG. The two major aims are 1) to analyze the substrate profile of POMGnT1, an enzyme involved in a key step in the O-Man glycan assembly whose defects are associated with muscle-eye-brain disease, to better understand how rescue the defect and to develop a better assay for detection of defective enzyme, and 2) to elucidate the activity of polypeptide GalNAc transferases in initiating O-GalNAc sites on 1-DG and the relationship of these to POMGnT1 glycosylation. PUBLIC HEALTH RELEVANCE: Several forms of muscular dystrophy are associated with aberrations in the attachment of carbohydrates to the glycoprotein 1-dystroglycan arising from defects in the enzymes that carry out the complex series of steps leading to the specific installation of carbohydrates on it. The proposed research would use an integrated approach combining chemical synthesis of glycopeptides from1- dystroglycan, biochemical analysis of their modification by glycosyltransferase enzymes, and structural analysis of the reactants and products, to develop an understanding at a molecular level of the post-translational modification of this important glycoprotein. The information derived will contribute to understanding the pathological mechanisms of several forms of muscular dystrophies, improving clinical assay, and rational design of therapeutic interventions.

描述（由申请人提供）：拟议研究的目的是了解1-多糖糖（1-DG）的翻译后加工，这是一种糖蛋白，是一种糖蛋白，是营养不良蛋白 - 糖蛋白复合蛋白复合物的关键成分，将肌肉细胞锚定在细胞外基质上。 1-DG在其高度保守的中央粘蛋白样区域的糖基化有缺陷，糖基化的S和T残基是多种形式的遗传性肌肉营​​养不良的原因。 N-乙酰葡萄糖（GALNAC）或更不寻常的甘露糖（MAN）残基将吊坠聚糖与蛋白质相关联，其部位现在只是被映射的。已经建立了O-Man四糖和疾病的组装问题之间的关系。我们最近发现了GalNAC残基在结构上很重要的证据。合成，生化和结构方法将集成在研究中，以发展对这一复杂过程中的步骤的理解，从而对酶促转化进行定量描述，并促进对1-DG参与的关键相互作用的见解。对此过程中的步骤的理解将为理性设计纠正缺陷的理性设计提供基础，包括基因疗法和可能补充有缺陷酶的其他酶的上调。重点将在1-DG的初始O-MAN修改之后的两个步骤上。 The two major aims are 1) to analyze the substrate profile of POMGnT1, an enzyme involved in a key step in the O-Man glycan assembly whose defects are associated with muscle-eye-brain disease, to better understand how rescue the defect and to develop a better assay for detection of defective enzyme, and 2) to elucidate the activity of polypeptide GalNAc transferases in initiating O-GalNAc sites on 1-DG及其与POMGNT1糖基化的关系。 公共卫生相关性：几种形式的肌营养不良症与碳水化合物附着在糖蛋白1-脱糖尿的附着的畸变有关，这是由于酶的缺陷引起的，这些酶在其上执行了一系列复杂的步骤，从而导致其在其上进行特定的碳水化合物。拟议的研究将采用一种综合方法，该方法结合了从1-二种糖的化学合成，对通过糖基转移酶修饰的生化分​​析以及对反应剂和产物的结构分析，以在这种重要的糖蛋白细胞的转移后修饰的分子水平上发展一种理解。得出的信息将有助于理解几种形式的肌肉营养不良的病理机制，改善临床测定以及治疗干预的合理设计。