V-ATPase H+ PUMP REGULATION IN FUEL ENERGY SELECTION

燃料能量选择中的 V-ATPase H 泵调节

• 批准号: 8078880
• 负责人: Karlett J Parra
• 金额: $ 34.38万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8078880
• 关键词: Acetyl Coenzyme A; Acid-Base Equilibrium; Address; African American; Alaska Native; Aldehyde-Lyases; American Indians; Bacterial Toxins; Binding; Biochemical; Biological Models; Carbon; Cell membrane; Cells; Chronic Kidney Failure; Citrates; Complement; Complex; Coupled; Couples; Defect; Development; Diabetes Mellitus; Disease; Elements; Endosomes; Energy Metabolism; Enzymes; Ethnic group; Fatty Acids; Fatty acid glycerol esters; Fructose; Functional disorder; Genetic; Glucose; Glycolysis; Goals; Health; Hispanics; In Vitro; Insulin Resistance; Intercalated Cell; Kidney; Kidney Diseases; Knowledge; Link; Lysosomes; Macromolecular Complexes; Malignant Neoplasms; Malonyl Coenzyme A; Measures; Membrane; Metabolic; Metabolic Control; Metabolic Diseases; Metabolism; Modeling; Molecular; Molecular Structure; Nephrons; Nutrient; Obesity; Organism; Pathway interactions; Physiology; Process Measure; Proteins; Proton Pump; Protons; Public Health; Pump; Quality of life; Race; Regulation; Research; Risk Factors; Saccharomyces cerevisiae; Signal Transduction; Sorting - Cell Movement; Source; Structure; System; Testing; Vacuole; Virus; Warburg Effect; Yeast Model System; Yeasts; cancer cell; extracellular; fatty acid metabolism; fatty acid oxidation; glucose metabolism; in vivo; insight; interest; kidney cell; lipid metabolism; lysosome membrane; metabolic abnormality assessment; mutant; novel; oxidation; pH Homeostasis; reconstitution; response; vacuolar H+-ATPase

DESCRIPTION (provided by applicant): V-ATPases are conserved proton pumps important to pH homeostasis. Located at the membrane of lysosomes, vacuoles and endosomes, V-ATPases sustain the acidic luminal pH needed for protein sorting and degradation; and for entry of viruses and bacterial toxins into host cells. Cells specialized for active proton secretion such as the 1-intercalated cells of the kidney nephron, express V-ATPases at the plasma membrane where they fine-tune the systemic acid-base balance. It is our goal to demonstrate the fundamental mechanisms that carefully regulate V-ATPase function and assembly in order to gain insight into how V- ATPases assist in controlling luminal, cytosolic, and extracellular pH. V-ATPases are dynamic structures that reversibly disassemble to control pH. In yeast and kidney cells, activity and V-ATPase assembly are coupled with glycolysis, but the mechanisms involved are unclear. Using yeast model systems, we have shown a novel link between V-ATPases and the glucose-fatty acid cycle, suggesting that glucose and lipid metabolism remodel pH homeostasis via effects on V-ATPases. It is our hypothesis that V-ATPase assembly is regulated as a means of maintaining cellular pH homeostasis when metabolism switches between glucose and fatty acids. We propose that a complex consisting of the V-ATPase pump and glycolytic enzymes functionally and structurally couples pH homeostasis and energy metabolism; and that metabolic control of this macromolecular structure regulates V-ATPase assembly. Three specific aims will test this model: Aim 1 will dissect the metabolic signals that link V-ATPase to the glycolytic pathway; Aim 2 will elucidate the mechanisms by which regulation of glycolytic enzymes remodels V-ATPase assembly and activity; and Aim 3 will establish how activation of the glucose-fatty acid cycle cross-talks to V-ATPases. In order to accomplish the aims proposed, this study will measure V-ATPase assembly and disassembly in vma mutants and metabolic mutants deficient in key steps of glycolysis, 2- oxidation of fatty acids, and the glucose-fatty acid cycle. Parallels will be established between intracellular levels of metabolic intermediates and dynamics of binding between V-ATPase and glycolytic enzymes enabling us to understand how V-ATPases assist cells in adjusting to metabolic changes. Because of the complexity involved in both comprehensive metabolic studies and regulation of V-ATPase pumps by reversible disassembly, S. cerevisiae is an outstanding system to address this mechanism at both the genetic and biochemical levels. By showing the contribution of V-ATPases, new insights into the mechanisms that tune fuel energy selection will emerge. Cancer cells use V-ATPases to regulate pH as a result of changes in metabolism; thus new knowledge on the mechanisms by which V-ATPases maintain pH homeostasis in cancer may be revealed. As pathophysiology of the glucose-fatty acid cycle results in metabolic disorders including diabetes and chronic kidney disease, our studies will also contribute towards their understanding. PUBLIC HEALTH RELEVANCE: Diabetes is a major risk factor for the development and progression of chronic kidney disease (CKD). Diabetes and CKD are important public health problems; both are serious conditions associated with decreased quality of life and have disproportionate impact on certain racial and ethnic groups, especially African Americans, American Indians or Alaska Natives, and Hispanics. This study which focuses on a major problem seen in diabetes and CKD: interconnection between glucose and fats.

描述（由申请人提供）：v - atp酶是对pH稳态很重要的保守质子泵。v - atp酶位于溶酶体、液泡和核内体的膜上，维持蛋白质分选和降解所需的酸性腔内pH；以及病毒和细菌毒素进入宿主细胞。专门用于活跃质子分泌的细胞，如肾肾素的1插层细胞，在质膜上表达v - atp酶，在那里它们微调全身酸碱平衡。我们的目标是证明精心调节V- atp酶功能和组装的基本机制，以便深入了解V- atp酶如何协助控制腔内，胞质和细胞外ph。V- atp酶是可逆分解以控制ph的动态结构。在酵母和肾细胞中，活性和V- atp酶组装与糖酵解相结合，但所涉及的机制尚不清楚。利用酵母模型系统，我们发现了v - atp酶与葡萄糖-脂肪酸循环之间的新联系，表明葡萄糖和脂质代谢通过对v - atp酶的影响来重塑pH稳态。我们的假设是，当代谢在葡萄糖和脂肪酸之间转换时，v - atp酶组装作为维持细胞pH稳态的一种手段受到调节。我们认为一个由v - atp酶泵和糖酵解酶组成的复合物在功能和结构上耦合了pH稳态和能量代谢；这种大分子结构的代谢控制调节了v - atp酶的组装。三个特定的目标将测试该模型：目标1将剖析连接v - atp酶与糖酵解途径的代谢信号；目的2将阐明糖酵解酶调节v - atp酶组装和活性的机制；Aim 3将确定葡萄糖-脂肪酸循环的激活如何与v - atp酶交叉对话。为了实现上述目标，本研究将测量vma突变体和缺乏糖酵解、脂肪酸2-氧化和葡萄糖-脂肪酸循环关键步骤的代谢突变体中v - atp酶的组装和拆卸。将在细胞内代谢中间体水平和v - atp酶与糖酵解酶之间的结合动力学之间建立相似之处，使我们能够了解v - atp酶如何协助细胞适应代谢变化。由于综合代谢研究和v - atp酶泵可逆分解调控的复杂性，酿酒酵母在遗传和生化水平上都是解决这一机制的杰出系统。通过展示v - atp酶的作用，对调节燃料能量选择机制的新见解将会出现。癌细胞利用v - atp酶来调节pH值，这是新陈代谢变化的结果；从而揭示v - atp酶在癌症中维持pH稳态的机制。由于葡萄糖-脂肪酸循环的病理生理导致代谢紊乱，包括糖尿病和慢性肾脏疾病，我们的研究也将有助于他们的理解。公共卫生相关性：糖尿病是慢性肾脏疾病（CKD）发生和发展的主要危险因素。糖尿病和慢性肾病是重要的公共卫生问题；这两种疾病都是与生活质量下降相关的严重疾病，对某些种族和族裔群体的影响尤为严重，尤其是非洲裔美国人、美洲印第安人或阿拉斯加原住民以及西班牙裔美国人。这项研究的重点是糖尿病和慢性肾病的一个主要问题：葡萄糖和脂肪之间的相互联系。