Role of Phospholipase D in Glut-4 translocation

磷脂酶 D 在 Glut-4 易位中的作用

• 批准号: 6867418
• 负责人: Michael A. Frohman
• 金额: $ 28.73万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6867418
• 关键词: CHO cells; adipocytes; cell membrane; endocytosis; enzyme activity; enzyme mechanism; fluorescence microscopy; gene expression; glucose transport; glucose transporter; immunocytochemistry; insulin; muscle cells; phospholipase D; transfection

DESCRIPTION (provided by applicant): Insulin-stimulated glucose uptake in muscle and adipose tissue is primarily mediated by the insulin-responsive glucose transporter isoform, Glut-4. In the basal state, Glut-4 slowly cycles with the majority of the protein sequestered into intracellular storage sites. In response to insulin, the rate of Glut-4 exocytosis becomes markedly increased, resulting in a large accumulation of Glut-4 at the cell surface. Recent findings have suggested that this translocation process may be regulated by Phospholipase D (PLD), a membrane-associated enzyme that is also activated by insulin. PLD catalyzes the hydrolysis of phosphatidylcholine, the most abundant membrane phospholipid, to generate the signaling lipid phosphatidic acid (PA). PA has been proposed to have several cellular functions including the facilitation of membrane vesicle trafficking. There are two mammalian PLD genes, PLD1 and PLD2. We have recently shown that PLD1 facilitates the fusion of neuroendocrine secretory granules into the plasma membrane during regulated exocytosis and that both genes facilitate regulated exocytosis of mast cell histamine-containing granules. Importantly, the fusion mechanisms controlling these secretory granules have many features in common with the insulin-stimulated plasma membrane fusion of Glut-4 vesicles, and we have found recently that PLD1 and PLD2 activation or inhibition alters insulin-stimulated Glut-4 translocation to the plasma membrane. Based upon these novel data, we propose to examine systematically the function of PLD as a key regulatory component in the insulin-stimulated trafficking of Glut-4 by developing reconstitution assays and establishing the role of PLD in physiologically relevant contexts.

描述（由申请人提供）：肌肉和脂肪组织中胰岛素刺激的葡萄糖摄取主要由胰岛素响应性葡萄糖转运蛋白亚型 Glut-4 介导。在基础状态下，Glut-4 缓慢循环，大部分蛋白质被隔离到细胞内储存位点。在胰岛素的作用下，Glut-4 胞吐速率显着增加，导致 Glut-4 在细胞表面大量积累。最近的研究结果表明，这种易位过程可能受到磷脂酶 D (PLD) 的调节，磷脂酶 D 是一种膜相关酶，也可由胰岛素激活。 PLD 催化磷脂酰胆碱（最丰富的膜磷脂）的水解，生成信号脂质磷脂酸 (PA)。 PA 被认为具有多种细胞功能，包括促进膜囊泡运输。哺乳动物有两个 PLD 基因：PLD1 和 PLD2。我们最近表明，PLD1 在受调节的胞吐作用期间促进神经内分泌分泌颗粒融合到质膜中，并且这两个基因都促进肥大细胞含组胺颗粒的受调节的胞吐作用。重要的是，控制这些分泌颗粒的融合机制与胰岛素刺激的 Glut-4 囊泡质膜融合有许多共同特征，我们最近发现 PLD1 和 PLD2 的激活或抑制会改变胰岛素刺激的 Glut-4 易位到质膜。基于这些新数据，我们建议通过开发重构测定并确定 PLD 在生理相关环境中的作用，系统地检查 PLD 作为胰岛素刺激的 Glut-4 运输中关键调节成分的功能。