Mitochondrial Protein Acetylation and Energy Metabolism in Muscle

肌肉中线粒体蛋白乙酰化和能量代谢

• 批准号: 9408119
• 负责人: Ashley Silberman Williams
• 金额: $ 0.1万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-29 至 2017-04-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9408119
• 关键词: Ablation; Acetyl Coenzyme A; Acetylation; Acetylcarnitine; Affect; Age; Aging; Anabolism; Biochemical; Buffers; Carbon; Carnitine; Carnitine O-Acetyltransferase; Catabolism; Cell Culture Techniques; Cells; Chronic; Data; Deacetylase; Deacetylation; Diabetes Mellitus; Diet; Dietary Supplementation; Disease; Energy Metabolism; Environment; Enzymes; Event; Excision; Exercise; Exercise Tolerance; Exhibits; Fatty acid glycerol esters; Functional disorder; Glucose; Glucose Intolerance; Glycolysis; High Fat Diet; Homeostasis; Impairment; In Vitro; Insulin; Isotopes; Knock-out; Laboratory Study; Lead; Link; Lysine; Mass Spectrum Analysis; Measures; Mediating; Membrane; Metabolic; Metabolic Control; Metabolic Diseases; Methods; Mitochondria; Mitochondrial Matrix; Mitochondrial Proteins; Molecular; Multienzyme Complexes; Mus; Muscle; Muscle Cells; Muscle satellite cell; Nutrient; Obese Mice; Obesity; Oxidative Phosphorylation; Oxidative Stress; Performance; Physiological; Post-Translational Protein Processing; Production; Protein Acetylation; Proteins; Pyruvate; Reaction; Regulation; Research; Rodent Model; Role; SOD2 gene; Sirtuins; Site; Skeletal Muscle; Stimulus; Supplementation; Tamoxifen; Techniques; Testing; Therapeutic; acyl group; amino group; base; blood glucose regulation; energy balance; enzyme activity; exercise intolerance; feeding; flexibility; glucose metabolism; glucose tolerance; glucose uptake; improved; insight; insulin sensitivity; metabolic profile; metabolomics; mitochondrial dysfunction; muscle metabolism; nicotinamide-beta-riboside; oxidation; public health relevance; pyruvate dehydrogenase; respiratory; response; therapeutic target

 DESCRIPTION (provided by applicant): This project examines the role of protein acetylation in mediating nutrient-induced mitochondrial dysfunction. Lysine acetylation (AcK) has emerged as an important reversible post-translational modification. The biochemical environment of the mitochondrial compartment is particularly favorable for acetylation and recent studies have identified multiple AcK sites on a large number of mitochondrial proteins, including several metabolic enzymes and proteins involved in oxidative phosphorylation. Increased mitochondrial AcK levels correlate with metabolic dysfunction in the context of aging and obesity. A growing body of evidence suggests that acetylation of specific lysine residues on mitochondrial proteins impairs metabolic regulation leading to glucose intolerance, and compromises skeletal muscle performance during exercise. The protein responsible for deacetylation within the mitochondria, sirtuin 3 (SIRT3), has been identified. However the molecular events that promote mitochondrial AcK remain poorly understood. Acetyl-coenzyme A (CoA), a metabolic intermediate of glucose and fat catabolism, is the proposed substrate required for reversible acetylation. In vitro studies suggest mitochondrial AcK can occur non-enzymatically as a result of elevated mitochondrial acetyl-CoA production and/or accumulation. In addition, recent studies of the mitochondrial matrix enzyme, carnitine acetyltransferase (CrAT) underscore an important link between elevated acetyl-CoA levels, mitochondrial AcK and metabolic regulation. CrAT converts acetyl-CoA to its membrane permeate carnitine conjugate, acetylcarnitine. The CrAT reaction permits the mitochondrial efflux of excess acetyl groups and thereby has the potential to influence AcK events that are driven by mass action. This prediction is supported by preliminary studies from the laboratory showing that CrAT deficiency in mice exacerbates mitochondrial AcK in response to nutrient excess. Furthermore, CrAT ablation in the skeletal muscle results in metabolic dysfunction and exercise intolerance. The objective of this proposal is to determine if lysine acetylation of mitochondrial proteins contributes to the metabolic consequences of CrAT deficiency. The proposed studies will focus upon the molecular and physiological characterization of CrAT deficient cells and mice. First, we will test the hypothesis that stimuli that decrease mitochondrial acetylation can restore metabolic function in CrAT deficient myocytes. Second, we will use mice with a muscle-specific deletion of CrAT to determine whether normalization of mitochondrial AcK status restores glucose and/or exercise tolerance in the absence muscle CrAT. The results from these studies will expand our understanding of the functional relevance of mitochondrial AcK and could lead to the identification of therapeutic targets for treating age- and obesity- related skeletal muscle metabolic dysfunction and exercise intolerance.

 描述（由申请人提供）：本项目研究蛋白质乙酰化在介导营养诱导的线粒体功能障碍中的作用。赖氨酸乙酰化（AcK）是一种重要的可逆性翻译后修饰。线粒体区室的生化环境特别有利于乙酰化，最近的研究已经在大量线粒体蛋白上鉴定出多个AcK位点，包括参与氧化磷酸化的几种代谢酶和蛋白质。线粒体AcK水平增加与衰老和肥胖背景下的代谢功能障碍相关。越来越多的证据表明，线粒体蛋白上特定赖氨酸残基的乙酰化损害代谢调节，导致葡萄糖耐受不良，并在运动期间损害骨骼肌性能。已经鉴定了负责线粒体内脱乙酰化的蛋白质，sirtuin 3（SIRT 3）。然而，促进线粒体AcK的分子事件仍然知之甚少。乙酰辅酶A（CoA）是葡萄糖和脂肪催化剂的代谢中间体，是可逆乙酰化反应所需的底物。体外研究 提示线粒体AcK可作为线粒体乙酰辅酶A产生和/或积累增加结果而非酶促发生。此外，最近对线粒体基质酶肉毒碱乙酰转移酶（CrAT）的研究强调了乙酰辅酶A水平升高、线粒体AcK和代谢调节之间的重要联系。CrAT将乙酰辅酶A转化为其膜渗透肉毒碱缀合物，乙酰肉毒碱。CrAT反应允许过量乙酰基的线粒体流出，从而有可能影响由质量作用驱动的AcK事件。这一预测得到了实验室初步研究的支持，这些研究表明，小鼠中CrAT缺乏会加剧线粒体AcK对营养过剩的反应。此外，骨骼肌中的CrAT消融导致代谢功能障碍和运动不耐受。本提案的目的是确定线粒体蛋白的赖氨酸乙酰化是否有助于CrAT缺乏的代谢后果。拟议的研究将集中在CrAT缺陷细胞和小鼠的分子和生理特征。首先，我们将测试的假设，即刺激减少线粒体乙酰化可以恢复代谢功能CrAT缺陷的肌细胞。其次，我们将使用肌肉特异性缺失CrAT的小鼠来确定线粒体AcK状态的正常化是否在缺乏肌肉CrAT的情况下恢复葡萄糖和/或运动耐量。这些研究的结果将扩大我们对线粒体AcK功能相关性的理解，并可能导致确定治疗年龄和肥胖相关的骨骼肌代谢功能障碍和运动不耐受的治疗靶点。