Molecular Mechanisms of Arrestin-Domain Containing Proteins in Metabolism

含有抑制蛋白结构域的蛋白质在代谢中的分子机制

• 批准号: 10320336
• 负责人: RICHARD T LEE
• 金额: $ 42.25万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10320336
• 关键词: Address; Amino Acid Sequence; Amino Acid Substitution; Amino Acids; Arrestins; Binding; Biochemical; Biochemistry; C-terminal; Carrier Proteins; Cells; Collaborations; Crystallization; Cysteine; Data; Diabetes Mellitus; Disease; Family; Family member; Fructose; G Protein-Coupled Receptor Signaling; Glucose; Glucose Clamp; Glucose Transporter; High Fat Diet; In Vitro; Insulin; Insulin Receptor; Investigation; Laboratories; Link; Manuscripts; Metabolic; Metabolism; Molecular; Mus; Mutation; Obesity; Oxidation-Reduction; Paper; Pathway interactions; Play; Prediabetes syndrome; Proteins; Reporting; Role; SLC2A1 gene; Structure; TXN gene; TXNIP gene; Tail; Testing; Tissues; United States; Visual; arrestin 1; beta-arrestin; blood glucose regulation; experimental study; glucose metabolism; glucose uptake; glucose-regulated proteins; human male; improved; in vivo; insulin sensitivity; insulin signaling; member; metabolic abnormality assessment; metabolic phenotype; molecular imaging; mouse model

The arrestin superfamily is composed of two subfamilies: the classical visual/beta-arrestins that were first identified as regulators of G-protein coupled receptor signaling, and the more ancient branch of arrestin domain-containing proteins that are sometimes called the “alpha-arrestins”. Recently, the roles of some members of the alpha-arrestin family have been revealed in mammalian metabolism. The most studied member of the alpha-arrestin family is thioredoxin interacting protein (TXNIP), which regulates glucose and fructose metabolism. Arrestin domain-containing 4 (ARRDC4) is a member of the alpha-arrestin family that has not been subject to extensive investigation. The arrestin domains of ARRDC4 show 41% amino acid sequence similarity to TXNIP; therefore, ARRDC4 might be expected to have functions similar to TXNIP. However, we have shown that TXNIP is the only member of the family that binds covalently to thioredoxin. Consistent with our biochemistry studies, the recently solved crystal structure revealed that the cysteine 247 residue of TXNIP is essential for binding covalently to thioredoxin. Furthermore, we have reported that mice with deletion of TXNIP have improved insulin sensitivity, indicating a potential like between redox state and glucose metabolism through thioredoxin. Here we show new unpublished experiments revealing that mice with global deletion of arrdc4 have improved insulin sensitivity. We also show improved insulin signaling in metabolic tissues from mice with deletion of arrdc4. Our preliminary data demonstrate that the ARRDC4 protein interacts directly with glucose transporter protein 4 (GLUT4) in insulin-stimulated conditions. Furthermore, we present a new mouse model with mutation of C247 of TXNIP and show that this single amino acid change in TXNIP improves insulin sensitivity in mice fed a High Fat Diet. In this project, we will use these new discoveries and mouse models to understand how arrestin domain-containing proteins regulate glucose metabolism in vivo and at the molecular mechanism level. Our Specific Aims are: Specific Aim 1 will test the hypothesis that alpha-arrestin protein ARRDC4 regulates insulin-stimulated glucose uptake in vivo. Specific Aim 2 will investigate the molecular mechanisms of alpha arrestin domain-containing protein interactions with glucose transporters and insulin receptor. Specific Aim 3 will test the hypothesis that TXNIP can regulate insulin sensitivity through thioredoxin-independent mechanisms and identify the target tissue responsible.

抑制蛋白超家族由两个亚家族组成：经典的视觉/β-抑制蛋白，最初被鉴定为 G 蛋白偶联受体信号传导的调节剂，以及包含抑制蛋白结构域的蛋白质的更古老的分支，有时被称为“α-抑制蛋白”。最近，α-抑制蛋白家族的一些成员在哺乳动物代谢中的作用已被揭示。 α-抑制蛋白家族中研究最多的成员是硫氧还蛋白相互作用蛋白（TXNIP），它调节葡萄糖和果糖代谢。含抑制蛋白结构域 4 (ARRDC4) 是 α-抑制蛋白家族的成员，尚未经过广泛研究。 ARRDC4 的抑制蛋白结构域与 TXNIP 的氨基酸序列相似性为 41%；因此，ARRDC4 可能具有与 TXNIP 类似的功能。然而，我们已经证明 TXNIP 是该家族中唯一与硫氧还蛋白共价结合的成员。与我们的生物化学研究一致，最近解析的晶体结构表明，TXNIP 的半胱氨酸 247 残基对于与硫氧还蛋白共价结合至关重要。此外，我们还报道，删除 TXNIP 的小鼠胰岛素敏感性得到改善，这表明氧化还原状态和葡萄糖之间存在潜在的联系。 通过硫氧还蛋白进行代谢。在这里，我们展示了新的未发表的实验，表明 arrdc4 整体缺失的小鼠改善了胰岛素敏感性。我们还发现删除 arrdc4 的小鼠代谢组织中的胰岛素信号得到改善。我们的初步数据表明，ARRDC4 蛋白在胰岛素刺激条件下直接与葡萄糖转运蛋白 4 (GLUT4) 相互作用。此外，我们提出了一种带有 TXNIP C247 突变的新小鼠模型，并表明 TXNIP 中的这种单一氨基酸变化可提高高脂饮食小鼠的胰岛素敏感性。在这个项目中，我们将利用这些新发现和小鼠模型来了解含有抑制蛋白结构域的蛋白质如何在体内和分子机制水平上调节葡萄糖代谢。我们的具体目标是： 具体目标 1 将检验 α-抑制蛋白 ARRDC4 调节体内胰岛素刺激的葡萄糖摄取的假设。 具体目标 2 将研究含有 α 抑制蛋白结构域的蛋白质与葡萄糖转运蛋白和胰岛素受体相互作用的分子机制。 具体目标 3 将测试 TXNIP 可以通过硫氧还蛋白独立机制调节胰岛素敏感性的假设，并确定负责的靶组织。