Analyzing the role of TXNIP as a universal regulator of glucose transport

分析 TXNIP 作为葡萄糖转运通用调节剂的作用

• 批准号: 10004153
• 负责人: Ning Wu
• 金额: $ 39.9万
• 依托单位: VAN ANDEL RESEARCH INSTITUTE
• 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 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10004153
• 关键词: 1-Phosphatidylinositol 3-Kinase; 5' -AMP-activated protein kinase; Acute; Adipocytes; Adipose tissue; Affect; Arrestins; Biochemical; Biological; Biological Assay; Biological Process; Cancerous; Carrier Proteins; Cell membrane; Cells; Clathrin; Defect; Disease; Endocytosis; Environment; Event; Exercise; Family; Foundations; Future; G-Protein-Coupled Receptors; GLUT-1 protein; GLUT-3 protein; GLUT2 gene; GLUT4 gene; Glucose; Glucose Transporter; Growth; Growth Factor; Human; Hyperlipidemia; Hyperphagia; Hypoglycemia; In Vitro; Insulin; Investigation; Knockout Mice; Knowledge; Learning; Lipids; Location; Malignant Neoplasms; Maps; Mediating; Metabolic; Metabolic stress; Metabolic syndrome; Mitogen-Activated Protein Kinases; Modeling; Movement; Mus; Muscle; Muscle Fibers; Nutrient; Organism; Pathway interactions; Peripheral; Phenotype; Phosphatidylinositols; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological; Play; Post-Translational Protein Processing; Postabsorptive Hypoglycemia; Proteins; Proto-Oncogene Proteins c-akt; Regulation; Reporting; Role; SLC2A1 gene; Sequence Homology; Signal Transduction; Site; Stress; Structure; Symptoms; System; TXNIP gene; Testing; Tissues; Up-Regulation; Vitamin D; age related; blood glucose regulation; cell growth; cell type; extracellular; glucose metabolism; glucose transport; glucose uptake; human disease; in vivo; insight; insulin regulation; knockout animal; member; metabolic phenotype; metabolic profile; prevent; protein degradation; protein transport; prototype; response; solute; therapy development; tumor growth; upstream kinase

PROJECT SUMMARY Glucose is one of the most highly regulated metabolites for nearly all organisms. In humans, misregulation of glucose metabolism plays a role in many diseases, from systemic metabolic syndrome to cancerous cell growth. This proposal focuses on the glucose transporters (GLUTs) in the solute carrier family 2 (SLC2), which includes the well-known transporters GLUT1, GLUT2, GLUT3, and GLUT4. These transporters facilitate the movement of glucose across the cell membrane following concentration gradients in an energy-independent manner. Since GLUTs serve as gates between the cell and the extracellular environment, their activity must be tightly controlled by both signaling events and metabolite levels. Despite their key roles in the major metabolic tissues, very little is known about GLUT protein-level regulation. Insulin regulation of GLUT4 is the notable exception, but even in this case, many mechanistic details (such as insulin-dependent inhibition of GLUT4 endocytosis) remain unknown. We discovered that an α-arrestin protein, TXNIP (thioredoxin interacting protein), acts as an adaptor between GLUT1 and the clathrin-dependent endocytosis machinery, facilitating GLUT1 endocytosis. The interaction between TXNIP and GLUT1 is signal-dependent: phosphorylation of TXNIP by AMPK (AMP-activated kinase) dissociates TXNIP from GLUT1, preventing GLUT1 endocytosis, thus leading to a rapid increase in glucose influx. Given the sequence and structural homology among the GLUTs, together with signal-induced post- translational modifications found on the TXNIP protein, we aim to show that TXNIP is a universal regulatory node evolved for modulating acute glucose flux response. Specific Aim 1 will analyze the regulation of TXNIP on GLUTs, using GLUT1 as the prototype and developing a detailed map of its interaction through various biochemical assays. The information we learn about GLUT1 will be tested on other GLUTs, particularly GLUT4, to verify the role of TXNIP as a common adaptor for all GLUTs. In this Aim, we will also examine the role of lipids in TXNIP-GLUT interactions to build a foundation for future investigation of GLUT protein trafficking. Specific Aim 2 will focus on the upstream regulation of TXNIP by cell signaling events, particularly growth factor stimulation. We intend to identify upstream kinases and their phosphorylation sites on TXNIP; we also plan to test the effect of this regulation in vivo, using insulin regulation of glucose uptake in muscle and adipose tissue as the model. Muscle- and adipose-specific TXNIP knock-out mice will be generated to examine their metabolic profile. Combined understanding of the upstream and downstream regulatory mechanisms of TXNIP should provide greater insight into how glucose metabolism can be misregulated in human diseases.

项目概要 葡萄糖是几乎所有生物体中受最严格调控的代谢物之一。在人类中，调节不当 葡萄糖代谢在许多疾病中发挥作用，从全身代谢综合征到癌细胞 生长。该提案重点关注溶质载体家族 2 (SLC2) 中的葡萄糖转运蛋白 (GLUT)，该家族 包括众所周知的转运蛋白 GLUT1、GLUT2、GLUT3 和 GLUT4。这些运输工具有利于 葡萄糖在能量独立的环境中遵循浓度梯度穿过细胞膜的运动 方式。由于 GLUT 充当细胞和细胞外环境之间的大门，因此它们的活动必须是 受到信号事件和代谢物水平的严格控制。尽管它们在主要代谢中发挥着关键作用 对于组织中 GLUT 蛋白水平的调节知之甚少。 GLUT4 的胰岛素调节是值得注意的 例外，但即使在这种情况下，许多机制细节（例如 GLUT4 的胰岛素依赖性抑制） 内吞作用）仍然未知。 我们发现 α-arrestin 蛋白 TXNIP（硫氧还蛋白相互作用蛋白）充当 GLUT1 和网格蛋白依赖性内吞机制，促进 GLUT1 内吞作用。互动 TXNIP 和 GLUT1 之间的作用是信号依赖性的：AMPK（AMP 激活激酶）对 TXNIP 进行磷酸化 将 TXNIP 与 GLUT1 解离，阻止 GLUT1 内吞作用，从而导致葡萄糖快速增加 涌入。鉴于 GLUT 之间的序列和结构同源性，以及信号诱导的后 在 TXNIP 蛋白上发现翻译修饰，我们的目的是证明 TXNIP 是一种通用的调节剂 节点进化用于调节急性葡萄糖通量反应。 具体目标1将分析TXNIP对GLUT的调节，以GLUT1为原型，开发一个 通过各种生化测定其相互作用的详细图谱。我们了解到的有关 GLUT1 的信息将 在其他 GLUT（特别是 GLUT4）上进行测试，以验证 TXNIP 作为所有 GLUT 的通用适配器的作用。 在这个目标中，我们还将研究脂质在 TXNIP-GLUT 相互作用中的作用，为未来奠定基础 GLUT 蛋白质运输的调查。具体目标2将重点关注细胞对TXNIP的上游调控 信号事件，特别是生长因子刺激。我们打算鉴定上游激酶及其 TXNIP 上的磷酸化位点；我们还计划使用胰岛素调节来测试这种调节在体内的效果 以肌肉和脂肪组织中葡萄糖的摄取为模型。肌肉和脂肪特异性 TXNIP 敲除 将生成小鼠来检查它们的代谢特征。结合对上游和下游的了解 TXNIP 的下游调节机制应该可以更深入地了解葡萄糖代谢如何 在人类疾病中受到错误调控。