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.

项目摘要 葡萄糖是几乎所有生物体的最高度调节的代谢物之一。在人类中， 葡萄糖代谢在许多疾病中起作用，从全身代谢综合征到癌细胞 增长该建议的重点是溶质载体家族2（SLC 2）中的葡萄糖转运蛋白（GLUT）， 包括众所周知的转运蛋白GLUT 1、GLUT 2、GLUT 3和GLUT 4。这些转运蛋白促进了 葡萄糖在能量不依赖性的浓度梯度下穿过细胞膜的运动 方式由于GLUT充当细胞和细胞外环境之间的门，因此它们的活性必须是 由信号事件和代谢物水平紧密控制。尽管它们在主要代谢过程中起着关键作用， 组织中，对GLUT蛋白水平的调节知之甚少。胰岛素对GLUT 4的调节是值得注意的 但即使在这种情况下，许多机制的细节（如胰岛素依赖性抑制GLUT 4 内吞作用）仍然未知。 我们发现一种α-arrestin蛋白，TXNIP（硫氧还蛋白相互作用蛋白），作为一个衔接子， GLUT 1和网格蛋白依赖性内吞机制，促进GLUT 1内吞。的相互作用 TXNIP和GLUT 1之间的相互作用是信号依赖性的：TXNIP被AMPK（AMP激活的激酶）磷酸化 使TXNIP与GLUT 1解离，阻止GLUT 1内吞，从而导致葡萄糖快速增加 流入。考虑到GLUT之间的序列和结构同源性，以及信号诱导的后 通过对TXNIP蛋白的翻译修饰，我们的目的是表明TXNIP是一种通用的调节蛋白， 节点进化为调节急性葡萄糖流量反应。 具体目标1将分析TXNIP对GLUT的调节，以GLUT 1为原型，开发一种 通过各种生物化学测定其相互作用的详细图谱。我们了解到的关于GLUT 1的信息将 在其他GLUT上进行测试，特别是GLUT 4，以验证TXNIP作为所有GLUT的通用适配器的作用。 在这个目的中，我们还将研究脂质在TXNIP-GLUT相互作用中的作用，为将来的研究奠定基础。 研究GLUT蛋白运输。具体目标2将集中在细胞对TXNIP的上游调控 信号事件，特别是生长因子刺激。我们打算确定上游激酶及其 我们还计划在体内测试这种调节的效果，使用胰岛素调节 的葡萄糖摄取在肌肉和脂肪组织作为模型。肌肉和脂肪特异性TXNIP敲除 将产生小鼠以检查它们的代谢谱。结合对上游和 TXNIP的下游调节机制应该提供更深入的了解葡萄糖代谢如何 在人类疾病中被错误调节。