The Effects of Glucokinase Polymerization During Metabolic Transitions

葡萄糖激酶聚合在代谢转变过程中的影响

• 批准号: 9129541
• 负责人: patrick renwick stoddard
• 金额: $ 3.14万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2018-07-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9129541
• 关键词: Acceleration; Actins; Affect; Allosteric Regulation; Biochemical Pathway; Biochemistry; Biological; Biological Assay; Biological Process; Carbon; Cell Death; Cell Survival; Cells; Conflict (Psychology); Consumption; Cryoelectron Microscopy; Data; Dependence; Diabetes Mellitus; Environment; Enzymes; Ethanol; Fermentation; Filament; Flow Cytometry; Fluorescence Resonance Energy Transfer; Genes; Genetic; Glucokinase; Glucose; Glycolysis; Goals; Growth; Homeostasis; Investments; Kinetics; Lead; Life; Ligands; Malignant Neoplasms; Measures; Metabolic; Metabolism; Microscopy; Modeling; Nutrient; Phase Transition; Physiological; Play; Polymers; Population; Post-Translational Protein Processing; Production; Proteins; Proteolysis; Proteome; Reporter; Respiration; Risk; Role; Saccharomyces cerevisiae; Saccharomycetales; Site-Directed Mutagenesis; Source; Staging; Structural Models; Structure; Subgroup; Testing; Time; Variant; X-Ray Crystallography; Yeasts; alcohol exposure; cell growth; cell killing; cell type; experience; hexokinase; member; mutant; polymerization; pressure; public health relevance; response; structural biology; whole genome

 DESCRIPTION (provided by applicant): The major goal of this project is to understand how metabolic networks are regulated in response to sudden changes in the concentration of environmental nutrients. While we have a good understanding of central carbon metabolism in various steady states, it is unclear how these metabolic networks adapt to maintain viability on timescales that are too short to alter the composition of the proteome. We focus on how the first step in glycolysis is regulated when cells growing slowly on ethanol are exposed to high enough glucose concentrations to induce the high flux through glycolysis that supports rapid, fermentative growth. Starting glycolysis too fast can deplete ATP and kill cells. Preliminary studies suggest that polymerization of a metabolic enzyme plays a crucial role in regulating the kinetics of this transition. We have found that Glucokinase-1 (Glk1), one of the three enzymes responsible for catalyzing the first step in glycolysis, forms linear polymers when respiring cells encounter high glucose concentrations. Purified Glk1 forms polymers in the presence of glucose and ATP and polymerization inhibits Glk1's catalytic activity. Using genetics, we have demonstrated that deleting GLK1 reduces cell death but slows the acceleration of growth rate when respiring cells encounter glucose. Taking advantage of the conservation of glycolysis across all kingdoms of life, we will investigate the way that starved Saccharomyces cerevisiae's metabolism responds to sudden introduction into glucose-rich media as a tractable model for the general response to rapid increases in the environmental glucose concentration. We will tackle this problem at multiple scales: using a combination of genetics, biochemistry and microscopy to understand how Glk1 and its polymerization affect both glycolysis and cellular growth; using a combination of biochemistry and structural biology in order to elucidate how Glk1 polymerization reduces Glk1 enzymatic activity; and determining the conservation of these mechanisms.

 描述（由适用提供）：该项目的主要目标是了解如何根据环境养分浓度的突然变化来调节代谢网络。尽管我们对各种稳态中的中央碳代谢有很好的了解，但尚不清楚这些代谢网络如何适应可生存到太短而无法改变蛋白质组组成的时间尺度。当细胞在乙醇上缓慢生长时，如何调节糖酵解的第一步如何暴露于足够高的葡萄糖浓度，以通过支持快速，发酵生长的快速糖酵解诱导高通量。可以复制ATP并杀死细胞。初步研究表明，代谢酶的聚合在确定这种过渡的动力学方面起着至关重要的作用。我们发现，葡萄糖酶-1（GLK1）是负责催化糖酵解的第一步的三种酶之一，在呼吸细胞时形成线性聚合物 遇到高葡萄糖浓度。纯化的GLK1在葡萄糖和ATP存在下形成聚合物，聚合抑制GLK1的催化活性。使用遗传学，我们已经证明，删除GLK1可以减少细胞死亡，但在呼吸细胞遇到葡萄糖时会减慢生长速率的加速。利用在生活的所有王国中保存糖酵解，我们将研究饥饿的酿酒酵母对突然引入葡萄糖富含葡萄糖的培养基的代谢反应，作为对环境葡萄糖浓度快速增加的一般反应的一种可传输模型。我们将在多个尺度上解决这个问题：使用遗传学，生物化学和显微镜的组合来了解GLK1及其聚合如何影响糖酵解和细胞生长；使用生物化学和结构生物学的组合，以阐明GLK1聚合如何降低GLK1酶活性；并确定这些机制的保护。