N-Glycosylation And ER Stress

N-糖基化和 ER 应激

• 批准号: 7627089
• 负责人: Mark Lehrman
• 金额: $ 38.47万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7627089
• 关键词: Address; Asparagine; Binding; Biochemical; Calnexin; Carbohydrates; Cell Adhesion Molecules; Cell Communication; Cell physiology; Cell surface; Cells; Cholesterol; Chronic; Clinical; Congenital Disorders; Custom; Defect; Disease; Dolichol; Electrophoresis; Endoplasmic Reticulum; Enzymes; Fibroblasts; Functional disorder; Funding; Future; Glycogen; Glycoproteins; Grant; Hereditary Disease; Homeostasis; Human; Immunoglobulins; Insulin; Islets of Langerhans; Ketoconazole; Lectin; Life; Link; Mannose; Modeling; Modification; Molecular Chaperones; Monitor; Mutation; Obesity; PERK kinase; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphomannomutase; Plasma Cells; Polymers; Polypeptide Hormones; Polysaccharides; Process; Production; Productivity; Protein Glycosylation; Proteins; Publishing; Quality Control; Reaction; Receptor Signaling; Regulation; Research; Research Proposals; Role; Signal Pathway; Signal Transduction; Stress; Structure; Testing; Thinking; Work; analog; base; biological adaptation to stress; calreticulin; clinically relevant; concept; design; fluorophore; glycosylation; human disease; innovation; insight; lipooligosaccharide; mannose 6 phosphate; nervous system disorder; novel; polypeptide; protein folding; repaired; response; sugar; sugar nucleotide

Many vitally important proteins which are secreted (such as immunoglobulins and polypeptide hormones) or present at the cell surface (including cell adhesion molecules and signaling receptors) are produced and folded by the endoplasmic reticulum (ER). If the ER has problems folding these proteins, a compensatory ¿ER stress response¿ (a.k.a. Unfolded Protein Response) is triggered to enhance various ER-related folding processes. ER-produced proteins are frequently N-glycosylated with asparagine-bound sugar polymers (glycans). The glycans are intimately involved in folding of N-glycoproteins, and can also participate in their functions after secretion or reaching the cell surface. The ER-associated lipid-linked oligosaccharide (LLO) Glc3Man9GlcNAc2-P-P-dolichol provides the glycan (Glc3Man9GlcNAc2) used to make N-glycoproteins. There are 13 human genetic diseases (12 are untreatable), the ¿Congenital Disorders Of Glycosylation¿ (CDG-I) Types Ia-Im, with defective LLO synthesis. Thus, CDG-I cells have ER dysfunction due to poor Nglycosylation, and patients have many clinical difficulties. This research proposal explores the P.I.¿s discovery that LLO synthesis is one of the processes regulated by the ER stress response, and his hypothesis that the response can be co-opted pharmacologically to repair LLO synthesis abnormalities in CDG-I. Consequently research with this grant has led the P.I. to a new perspective, in which G3M9Gn2-P-P-Dol production is viewed not as a hard-wired process, but rather one which is constantly monitored and adjusted. AIM I will examine the ER stress response as an important regulator of levels of nucleotide-sugars, the biochemical precursors of glycans. AIM II will use CDG-I culture models to test whether pharmacologically-relevant ER stress modulators can counteract LLO synthesis defects, and whether LLO dysfunction in some CDG-I patients¿ cells is corrected by endogenously-triggered ER stress responses. AIMS III and IV will provide important new information about an unexpected activity of mannose-6-phosphate (M6P). The P.I. discovered that M6P is elevated by ER stress, and causes release of the glycan from Glc3Man9GlcNAc2-P-P-dolichol. AIM III will develop custom-synthesized analogues of M6P to elucidate its cellular action. AIM IV will explore the role of M6P-released glycans in ER homeostasis. The clinical relevance of this research is two-fold. First, new strategies for treating glycosylation-deficient human diseases will be evaluated, including some with existing drugs. Second, this work will generate new information about the ER stress response, which governs the productivity of the ER, is essential for the secretory functions of plasma cells (immunoglobulins) and pancreatic islets (insulin), and when aberrantly controlled can cause neurological diseases, cholesterol imbalance, and obesity.

分泌的许多非常重要的蛋白质（例如免疫球蛋白和多肽激素） 或存在在细胞表面（包括细胞粘合分子和信号接收器），并产生 由内质网（ER）折叠。如果ER在折叠这些蛋白质时遇到问题，则是补偿性的 触发应力反应（又称展开的蛋白质反应）​​以增强各种与ER相关的折叠 过程。 ER生产的蛋白经常用天冬酰胺结合的糖聚合物进行N-糖基化 （聚糖）。聚糖密切参与N-糖蛋白的折叠，也可以参与他们的 分泌后的功能或到达细胞表面。与ER相关的脂质连接寡糖（LLO） GLC3MAN9GLCNAC2-P-P-DOLICHOL提供用于生产N-糖蛋白的聚糖（GLC3MAN9GLCNAC2）。那里 是13种人类遗传疾病（12种是不可治疗的），糖基化的先天性疾病（CDG-I） IA-IM类型，具有有缺陷的LLO合成。这是由于nglycosylation不良，CDG-I细胞具有ER功能障碍， 患者有许多临床困难。该研究建议探讨了P.I.S的发现 LLO合成是由ER应力反应调节的过程之一，他的假设是 可以通过药物进行响应来修复CDG-I的LLO合成异常。最后 通过这笔赠款的研究领导了P.I.从新的角度来看，查看了G3M9GN2-P-P-DOL的生产 不是作为硬连线的过程，而是经常监控和调整的过程。目的我将检查 ER应激反应是核苷酸含量水平的重要调节剂，这是 聚糖。 AIM II将使用CDG-I培养模型来测试药物是否相关的ER应力 调节剂可以抵消LLO合成缺陷，以及某些CDG-I患者的LLO功能障碍是否功能障碍 通过内生触发的ER应力反应纠正。 AIMS III和IV将提供重要的新 有关甘露糖 - 6-磷酸（M6P）意外活动的信息。 P.I.发现M6P是 通过ER应力提升，并导致从GLC3MAN9GLCNAC2-P-P-P-DOLICHOL中释放聚糖。 AIM III会 开发M6P的定制合成类似物，以阐明其细胞作用。 AIM IV将探讨 M6P发行的er稳态中的聚糖。这项研究的临床相关性是两个方面。首先，新的 将评估治疗缺陷糖基化的人类疾病的策略，其中一些现有 毒品。其次，这项工作将生成有关ER压力响应的新信息，该信息控制 ER的生产力对于浆细胞（免疫球蛋白）和胰腺的秘密功能至关重要 胰岛（胰岛素），当被异常控制时会引起神经系统疾病，胆固醇失衡和 肥胖。