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.

许多重要的分泌蛋白质（如免疫球蛋白和多肽激素） 或存在于细胞表面（包括细胞粘附分子和信号传导受体）的细胞粘附分子被产生， 由内质网（ER）折叠。如果ER折叠这些蛋白质有问题， 应激反应未折叠蛋白质反应）被触发以增强各种ER相关的折叠 流程. ER产生的蛋白质通常被天冬酰胺结合的糖聚合物N-糖基化 （聚糖）。聚糖密切参与N-糖蛋白的折叠，并且还可以参与它们的功能。 在分泌或到达细胞表面后发挥作用。ER相关脂质连接寡糖（LLO） Glc 3 Man 9 GlcNAc 2-P-P-多萜醇提供用于制备N-糖蛋白的聚糖（Glc 3 Man 9 GlcNAc 2）。那里 有13种人类遗传性疾病（12种无法治疗），即先天性糖基化疾病（CDG-I） Ia-Im型，LLO合成有缺陷。因此，CDG-I细胞由于N糖基化差而具有ER功能障碍， 并且患者具有许多临床困难。这项研究计划探讨了P.I.的发现 LLO的合成是受ER应激反应调节的过程之一，他的假设是LLO的合成是受ER应激反应调节的过程之一。 反应可以被共同选择以修复CDG-I中的LLO合成异常。因此 利用这笔资金进行的研究使PI G3 M9 Gn 2-P-P-Dol生产的新视角 这不是一个固定的过程，而是一个不断监测和调整的过程。目的我将研究 内质网应激反应作为一个重要的调节水平的核苷酸糖，生化前体， 聚糖AIM II将使用CDG-I培养模型来测试药理学相关的ER应激是否 调节剂可以抵消LLO合成缺陷，以及一些CDG-I患者细胞中的LLO功能障碍是否 由内源性触发的内质网应激反应纠正。AIMS III和IV将提供重要的新 关于甘露糖-6-磷酸（M6 P）的意外活性的信息。私家侦探发现M6 P是 通过ER应激升高，并导致聚糖从Glc 3 Man 9 GlcNAc 2-β-β-多萜醇释放。AIM III将 开发定制合成的M6 P类似物，以阐明其细胞作用。AIM IV将探讨 ER稳态中的M6 P释放聚糖。这项研究的临床意义是双重的。一是新 将评估治疗糖基化缺陷人类疾病的策略，包括一些现有的 毒品第二，这项工作将产生关于ER应激反应的新信息，ER应激反应控制着细胞的生长。 ER的生产力，对于浆细胞（免疫球蛋白）和胰腺的分泌功能是必需的。 胰岛（胰岛素），当异常控制可导致神经系统疾病，胆固醇失衡， 肥胖