Mechanism of Activation of eEF-2K, an Energy and Nutrient Sensor

能量和营养传感器 eEF-2K 的激活机制

• 批准号: 9289618
• 负责人: Kevin N Dalby
• 金额: $ 41.57万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-15 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9289618
• 关键词: Accounting; Address; Affinity; Alpha Cell; Alzheimer' s Disease; Bacteria; Binding; Biochemical; Biological; Biological Assay; Biophysics; Calcium; Calcium ion; Calmodulin; Cell physiology; Cells; Complex; Cues; Disease; Disease Progression; Ensure; Equilibrium; Etiology; Eukaryotic Cell; Event; Family; Future; Goals; Homeostasis; In Vitro; Kinetics; Knock-out; Label; Learning; Length; Link; Malignant Neoplasms; Mammalian Cell; Mediating; Memory; Mental Depression; Molecular Conformation; NMR Spectroscopy; Nature; Neurons; Nuclear Magnetic Resonance; Nutrient; Peptide Elongation Factor 2; Peptides; Phase; Phosphorylation; Phosphotransferases; Physiological; Physiological Processes; Play; Preparation; Process; Protein Biosynthesis; Protein Kinase; Protein Phosphatase 2A Regulatory Subunit PR53; Proteins; Regulation; Ribosomes; Role; Signal Transduction; Site; Site-Directed Mutagenesis; Structure; Techniques; Testing; Time; Translations; Variant; Warburg Effect; base; calmodulin-dependent protein kinase III; cancer cell; collaborative approach; cost; design; glucose uptake; member; nutrient deprivation; protein degradation; protein kinase A kinase; response; sensor; spatiotemporal

ABSTRACT Protein synthesis (translation) constitutes one of the most fundamental of all cellular processes. The balance between protein synthesis and protein degradation is critical in maintaining cellular homeostasis. Translation is one of the most energy consumptive processes in a cell, accounting for as much as 30% of the energy usage in a eukaryotic cell, making its tight regulation a necessity. Eukaryotic elongation factor 2 kinase (eEF-2K), a unique member of the α-kinase family, is a key regulator of the elongation phase of translation. eEF-2K phosphorylates and inactivates elongation factor 2 (eEF-2), leading to a reduction in global translation rates on one hand and differential translation of certain proteins on the other. The activity of eEF-2K is dependent on calmodulin, and is subject to complex regulation by calcium ions and phosphorylation . While there is accumulating evidence that the dysregulation of eEF-2K activity is involved in several disease states (e.g. Alzheimer's disease, depression, and a variety of cancers), a detailed mechanistic understanding of eEF-2K activation and regulation is lacking. Our long-term goal is to precisely define the mechanisms by which eEF-2K is activated and regulated; such information is critical to understanding its contributions to both normal cellular processes and in the etiology and progression of disease states. Toward this goal, we recently identified calmodulin-stimulated autophosphorylation on a specific residue, T348, as being the key step in the activation of eEF-2K. Our objective in the present proposal is to describe the structural and biochemical mechanisms of eEF-2K activation by calmodulin and the roles of calcium and phosphorylation at a regulatory site, S500, in modulating this process. We will achieve this goal through a multi-faceted and collaborative approach that encompasses enzymological, kinetic, solution-state nuclear magnetic resonance and cell-biological techniques. Our central hypothesis is that T348 autophosphorylation and activation of eEF-2K is dependent on calmodulin binding. Calcium ions and S500 phosphorylation play overlapping roles but utilize distinct mechanisms in regulating the calmodulin sensitivity of eEF-2K and thereby its activation. We expect our analyses will provide the basis for a thorough mechanistic understanding of how eEF-2K integrates these two disparate signals that regulate its activity. Such a detailed picture of eEF-2K regulation is critical for elucidating its contribution to a variety of fundamental cellular process and its deregulation in a variety of disease states.

抽象的 蛋白质合成（翻译）是所有细胞过程中最基本的过程之一。 蛋白质合成和蛋白质降解之间的关系对于维持细胞稳态至关重要。 是细胞中最耗能的过程之一，占细胞能量消耗的30%之多 真核细胞，使其必须受到真核延伸因子 2 激酶 (eEF-2K) 的严格调控。 α-激酶家族的独特成员，是翻译延伸阶段的关键调节因子。 磷酸化并失活延伸因子 2 (eEF-2)，导致整体翻译率降低 一方面，某些蛋白质的差异翻译取决于 eEF-2K 的活性。 钙调蛋白，并受到钙离子和磷酸化的复杂调节。 越来越多的证据表明 eEF-2K 活性失调与多种疾病状态有关（例如， 阿尔茨海默病、抑郁症和多种癌症），对 eEF-2K 的详细机制了解 我们的长期目标是精确定义 eEF-2K 的激活和调节机制。 被激活和监管；此类信息对于理解其对正常情况的贡献至关重要 为了实现这一目标，我们最近确定了细胞过程以及疾病状态的病因和进展。 钙调蛋白刺激的特定残基 T348 上的自磷酸化是激活的关键步骤 我们当前提案的目标是描述 eEF-2K 的结构和生化机制。 钙调蛋白激活 eEF-2K 以及调节位点 S500 中钙和磷酸化的作用 我们将通过多方面的协作方法来调节这一过程。 包括酶学、动力学、溶液态核磁共振和细胞生物学技术。 我们的中心假设是 T348 自磷酸化和 eEF-2K 的激活依赖于 钙调蛋白结合和 S500 磷酸化发挥重叠作用，但利用不同的作用。 我们期待着调节 eEF-2K 钙调蛋白敏感性及其激活的机制。 分析将为全面理解 eEF-2K 如何集成这两者提供基础 调节 eEF-2K 活性的不同信号对于阐明 eEF-2K 调节至关重要。 它对各种基本细胞过程的贡献及其在各种疾病状态下的失调。