INSULIN REGULATION OF THE ADIPOCYTE GLUCOSE TRANSPORTER

胰岛素对脂肪细胞葡萄糖转运蛋白的调节

• 批准号: 2391318
• 负责人: GUSTAV E. LIENHARD
• 金额: $ 22.81万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-04-01 至 1998-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2391318
• 关键词: adipocytes; antibody; antisense nucleic acid; cell free system; cell membrane; glucose transport; guanine nucleotide binding protein; hormone regulation /control mechanism; immunoelectron microscopy; insulin; intracellular transport; laboratory rat; membrane proteins; membrane transport proteins; molecular biology; molecular cloning; phosphorylation; protein structure function; protein transport; recombinant DNA; vesicle /vacuole

Insulin stimulates the rate of glucose transport into adipocytes approximately 20-fold within ten minutes. This remarkable effect is largely due to the translocation of a specific isotype of the glucose transporter (Glut4) from within the cell to the plasma membrane. The long-term objective is to elucidate at the molecular level how this translocation of Glut4 occurs and is regulated by insulin. The intracellular Glut4 appears to be located in a specialized exocytotic vesicle, which is largely uncharacterized. The specific aims for the coming grant period are focused on characterizing components of this vesicle, as follows: (1) Other proteins specific to the Glut4 vesicles will be identified and their cDNAs will be cloned. Initially, this effort will be directed toward three groups of proteins for which we have preliminary data. These are: the synaptobrevins, a family of proteins previously considered to be located only in the synaptic and synaptic-like secretory vesicles; a 175 kD protein, which is a major component of the Glut4 vesicles and appears to translocate to the plasma membrane like Glut4; a group of three proteins in the 21-29 kD range that may be small guanine nucleotide binding proteins. (2) The properties and functions of these Glut4 vesicle proteins will be established. It will be determined whether each protein is colocalized with Glut4 in the rat adipocyte, whether it translocates to the plasma membrane in response to insulin, and whether its distribution among various tissues and cultured cells coincides with that of Glut4. The possible occurrence of specific associations between the different vesicle proteins will be examined. Potential functions for each of the newly defined proteins will be investigated by a variety of approaches, which will be guided by information about the structure of the protein and possibly its role in another context. For example, a potential role for a protein in the genesis of the Glut4 vesicle and/or the translocation process will be examined by attempting to block its expression in 3T3-L1 adipocytes with antisense oligonucleotides and RNA and by expressing the protein in cells that normally lack it. The proposed research is of direct relevance to the disease diabetes. A detailed knowledge of how insulin signals the translocation of Glut4 and how the process occurs may serve as the basis for the design of better therapeutic agents and/or regimes for both types I and II diabetes. Moreover, in the case of type II diabetes, where the basic cause(s) are not yet known, this knowledge may provide the framework for identifying a cause.

胰岛素刺激葡萄糖转运到脂肪细胞的速率 十分钟内翻了大约二十倍 这种显著的效果是 这主要是由于葡萄糖的特定同种型的易位 转运蛋白（Glut 4）从细胞内到质膜。 的 长期目标是在分子水平上阐明这一点， Glut 4的易位发生并受胰岛素调节。 的 细胞内Glut 4似乎位于一个专门的胞吐， 囊泡，这在很大程度上是uncharacterized。 的具体目标， 下一个赠款期的重点是表征这一组成部分， （1）Glut 4囊泡的其他特异性蛋白质 并克隆其cDNA。 原本这 我们将致力于研究三组蛋白质， 有初步数据。 它们是：突触小泡蛋白，一个家族， 蛋白质以前被认为只位于突触和 突触样分泌囊泡;一种175 kD的蛋白质，是一种主要的 Glut 4囊泡的组成部分，并似乎易位到 质膜样Glut 4;一组21-29 kD的三种蛋白质 范围，可能是小鸟嘌呤核苷酸结合蛋白。 (2)的 这些Glut 4囊泡蛋白的性质和功能将被 确立了习 将确定每种蛋白质是否共定位 与大鼠脂肪细胞中的Glut 4，它是否易位到血浆中 膜对胰岛素的反应，以及它是否分布在 各种组织和培养细胞中的Glut 4的表达与Glut 4的表达一致。 的 可能发生的具体联系之间的不同 将检测囊泡蛋白。 每一个潜在的功能， 新定义的蛋白质将通过多种方法进行研究， 它将由蛋白质结构的信息引导 以及它在另一个环境中的作用。 例如，潜在的 蛋白质在Glut 4囊泡和/或Glut 4囊泡形成中的作用 将通过尝试阻止其来检查易位过程 用反义寡核苷酸和RNA在3 T3-L1脂肪细胞中的表达 并在通常缺乏这种蛋白质的细胞中表达这种蛋白质。 这项拟议中的研究与糖尿病直接相关。 详细了解胰岛素如何发出Glut 4易位信号 以及该过程如何发生可以作为设计的基础， I型和II型的更好的治疗剂和/或方案 糖尿病 此外，在II型糖尿病的情况下， 原因尚不清楚，这些知识可以提供框架 找出原因