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: 8013758
• 负责人: Karlett J Parra
• 金额: $ 1万
• 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/8013758
• 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; 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; 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; in vivo; insight; interest; kidney cell; lipid metabolism; lysosome membrane; metabolic abnormality assessment; mutant; novel; oxidation; pH Homeostasis; public health relevance; racial and ethnic; 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稳态重要的保守质子泵。 V-ATP酶位于溶酶体，液泡和内体的膜上，维持了蛋白质分类和降解所需的酸性腔内pH。并将病毒和细菌毒素进入宿主细胞。专门用于活性质子分泌的细胞，例如肾脏肾单位的1个交流细胞，在质膜上表达V-ATPases，它们可以微调全身酸基平衡。我们的目标是证明仔细调节V-ATPase功能和组装的基本机制，以便深入了解V- ATPases如何帮助控制腔，胞质和细胞外pH。 V-ATPases是动态结构，可逆地拆卸以控制pH。在酵母和肾细胞中，活性和V-ATPase组装与糖酵解结合，但所涉及的机制尚不清楚。使用酵母模型系统，我们已经显示了V-ATPases与葡萄糖脂肪酸周期之间的新联系，这表明葡萄糖和脂质代谢重塑pH稳态通过对V-ATPase的影响。我们的假设是，当代谢在葡萄糖和脂肪酸之间切换时，V-ATPase组装被调节是维持细胞pH稳态的一种手段。我们提出，由V-ATPase泵和糖酵解酶在功能和结构上伴侣pH稳态和能量代谢组成。这种大分子结构的代谢控制调节V-ATPase组装。三个特定目标将测试该模型：AIM 1将剖析将V-ATPase与糖酵解途径联系起来的代谢信号； AIM 2将阐明调节糖酵解酶的机制。 AIM 3将确定如何激活葡萄糖酸性循环串扰对V-ATP酶。为了实现提出的目的，本研究将测量VMA突变体和代谢突变体中的V-ATPase组装，并在糖酵解的关键步骤，2-脂肪酸的氧化和葡萄糖脂肪酸循环中脱离。将在代谢中间体的细胞内水平与V-ATPase和糖酵解酶之间的结合动力学之间建立相似之处，从而使我们能够了解V-ATPases如何帮助细胞适应代谢变化。由于可逆拆卸的综合代谢研究和V-ATPase泵的调节涉及的复杂性，酿酒酵母是一个在遗传和生化水平下解决这种机制的杰出系统。通过显示V-ATP酶的贡献，对调节燃料能量选择的机制的新见解将出现。癌细胞使用V-ATP酶来调节新陈代谢的变化。因此，可以揭示有关V-ATP酶保持癌症中pH稳态的机制的新知识。由于葡萄糖酸周期的病理生理学导致包括糖尿病和慢性肾脏疾病在内的代谢疾病，我们的研究也将有助于其理解。公共卫生相关性：糖尿病是慢性肾脏疾病（CKD）发展和发展的主要危险因素。糖尿病和CKD是重要的公共卫生问题；两者都是与生活质量下降有关的严重条件，并且对某些种族和族裔，尤其是非裔美国人，美洲印第安人或阿拉斯加原住民以及西班牙裔人的影响不成比例。这项研究着重于糖尿病和CKD中的主要问题：葡萄糖和脂肪之间的互连。