Structural Determinants of Glycogen Synthase Regulation

糖原合酶调节的结构决定因素

• 批准号: 8187240
• 负责人: THOMAS D. HURLEY
• 金额: $ 37.97万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8187240
• 关键词: Active Sites; Affect; Agonist; American; Binding; Binding Sites; Biological Assay; Blood Glucose; Catalysis; Cell Culture Techniques; Cells; Complex; Development; Diabetes Mellitus; Diet; Digestive System Disorders; Discrimination; Disease; Enzymes; Exhibits; Family member; Galactose; Glucosamine; Glucose; Glucose-6-Phosphate; Glycogen; Glycogen (Starch) Synthase; Glycogen Storage Disease; Glycogen storage disease type II; Goals; Hand; Human; Individual; Institutes; Kidney Diseases; Lafora Disease; Lead; Link; Liver Glycogen; Mammalian Cell; Modeling; Molecular; Molecular Conformation; Monitor; Muscle; Mutagenesis; Non-Insulin-Dependent Diabetes Mellitus; Outcome; Pharmaceutical Preparations; Phosphorylation; Polymers; Process; Production; Property; Reaction; Regulation; Research; Screening procedure; Site; Specificity; Structure; Structure-Activity Relationship; Testing; Therapeutic; Uridine Diphosphate Glucose; Uridine Diphosphate Sugars; Work; Yeasts; analog; base; diabetic; feeding; glucose disposal; glycosyltransferase; high throughput screening; inhibitor/antagonist; insight; mutant; novel; prevent; small molecule; sugar nucleotide; tool

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand the structural and functional properties of the enzymes responsible for the synthesis and elongation of the glucose storage polymer, glycogen. Glycogen is an important storage reserve of glucose and the mechanism by which the synthesis of glycogen is initiated and elongated is conserved from yeast to humans. Our recent structural work on yeast glycogen synthase has provided important new insight into the functional properties of all eukaryotic enzymes. The long-range goal of this proposal is to build off this initial work to delineate the structural context for the reaction catalyzed by glycogen synthase and uncover the structural interplay between glycogen association and glucose-6- phosphate activation of glycogen synthase. As part of this effort, we will initialize a screen for small molecule modulators of human glycogen synthase that can manipulate the activity state of the enzyme and promote glucose disposal under conditions found in Type 2 Diabetes or inhibit the action of glycogen synthase as a potential approach for treating glycogen storage disorders, such as Lafora and Pompe's Disease. Structure determination will be an integral part or our efforts as complexes between glycogen synthase and its substrates in combination with glucose-6-phosphate or novel agonists/antagonists of the activator binding site will provide important structure/activity relationships that will guide further development of our research. As part of our screening efforts in Aim 2 we will produce novel enzymatic forms representing homogenous phosphorylation states and these will be tested against the novel modulators of glycogen synthase identified in this aim. In addition, we will pursue structure determination of these novel modulators in the presence and absence of substrates, substrate analogs or glucose-6-phosphate which will link to our work in aim 1. Aim 3 will determine the molecular mechanism of catalysis and the specificity of glycosyltransfer. One of the goals of this aim is to understand whether catalytic mistakes produced by glycogen synthase are ultimately responsible for aberrations in glycogen processing. This aim will draw upon the structural information developed in aim 1 and will employ wild-type and mutant forms of both yeast Gsy2p and human glycogen synthase and will feed important structure/activity information into our modulator discovery and development as part of aim 2. PUBLIC HEALTH RELEVANCE: The National Institute of Diabetes and Digestive and Kidney Disease and the American Diabetes Association estimate that greater than 20 million Americans suffer from Diabetes and that another 50 million Americans exhibit signs of impaired glucose utilization. Between one-third and two-thirds of the glucose in the diet is directed to our stores of glucose, muscle and liver glycogen. The work in this proposal is directed toward understanding the molecular mechanism the controls the activity of glycogen synthase and toward the development of potential drugs. These potential therapeutics would increase the ability of this enzyme to store blood glucose as glycogen, resulting in the lowering of blood glucose levels in Type 2 Diabetics, or inhibit the action of the enzyme and prevent over accumulation of glycogen in individuals with Pompe's or Lafora Disease.

描述(由申请人提供)：本提案的总体目标是了解负责合成和延长葡萄糖储存聚合物糖原的酶的结构和功能特性。糖原是葡萄糖的重要储备物，糖原合成的启动和延长机制从酵母到人类都是保守的。我们最近在酵母糖原合成酶方面的结构工作为了解所有真核酶的功能特性提供了重要的新见解。这项建议的长期目标是在这一初步工作的基础上，描绘由糖原合成酶催化的反应的结构背景，并揭示糖原结合和糖原合成酶的葡萄糖-6-磷酸激活之间的结构相互作用。作为这项工作的一部分，我们将启动人类糖原合酶小分子调节剂的筛选，这些小分子调节剂可以操纵酶的活性状态，并在2型糖尿病或抑制糖原合酶的作用下促进葡萄糖的处置，作为治疗糖原储存障碍的潜在方法，如Lafora和Pompe病。结构测定将是我们努力的一个组成部分，因为糖原合成酶及其底物与葡萄糖-6-磷酸或激活剂结合位点的新型激动剂/拮抗剂之间的络合物将提供重要的结构/活性关系，这将指导我们研究的进一步发展。作为我们在目标2中筛选工作的一部分，我们将产生代表均一磷酸化状态的新的酶形式，并将这些形式与在该目标中确定的糖原合成酶的新调节剂进行测试。此外，我们将在底物、底物类似物或葡萄糖-6-磷酸存在和不存在的情况下对这些新型调节剂进行结构测定，这将与我们在目标1中的工作相联系。目标3将确定催化的分子机制和糖基转移的特异性。这一目标的目的之一是了解糖原合成酶产生的催化错误是否最终导致糖原加工过程中的异常。这一目标将利用目标1中开发的结构信息，并将使用酵母Gsy2p和人糖原合成酶的野生型和突变形式，并将作为目标2的一部分，为我们的调节剂发现和开发提供重要的结构/活性信息。 与公共健康相关：美国国家糖尿病和消化及肾脏疾病研究所和美国糖尿病协会估计，超过2000万美国人患有糖尿病，另有5000万美国人表现出葡萄糖利用受损的迹象。饮食中三分之一到三分之二的葡萄糖直接用于我们储存的葡萄糖、肌肉和肝糖原。这项建议中的工作旨在了解控制糖原合成酶活性的分子机制，并开发潜在的药物。这些潜在的疗法将提高这种酶以糖原形式储存血糖的能力，从而降低2型糖尿病患者的血糖水平，或者抑制这种酶的作用，防止患有庞培病或拉福拉病的人体内糖原过度积累。