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Distribution sugar transporter isoforms and their regulation in the kidney

糖转运蛋白亚型的分布及其在肾脏中的调节

基本信息

批准号：
11671535
负责人：
FUJIKURA Keiko
金额：
$ 1.98万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

Various transporters, channels, pumps play important roles in the transfer of substances in the kidney. Precise localization and function of these molecules in the kidney are yet to be determined. In this project, we analyzed the localization of sugar transporters and organic cation transporters in the rat kidney. Fructose transporter GLUT5 was concentrated in the apical plasma membrane of S3 segment of proximal tubules in the outer stripe of the outer medulla. Insulin-recruitable sugar transporter GLUT4 was expressed in the cells of Henle's loop. It was localized intracellular compartments especially in the Golgi area including trans-Golgi network. In addition, it was localized in the endosomes. The dynamics of GLUT4 in the cell was analyzed in 3T3-L1 cells expressing green fluorescent protein (GFP)-tagged GLUT4 by the time-lapse microscopy of living cells. GLUT4-GFP was concentrated in the perinuclear region. Branching and fusion of GFP-GLUT4 were seen in this Golgi area. In the GFP-GLUT4 vesicles scattered in the cytoplasm, three types of movement were observed : One is immobile and remained in the same position. The second type of vesicles moved rapidly along the straight line for a long distance. The third type reciprocally moved, rapidly changing the direction of the motion. Organic cation transporters rOCTl and rOCT2 are expressed in the kidney, and their localization was visualized immunfluorescent technique. rOCTl was localized in the convoluted proximal tubules in the cortex, whereas rOCT2 was straight proximal tubules in the outer stripe of the outer medulla. Both transporters were localized along the basolateral plasma membrane, suggesting their role in the transfer of organic cations in the proximal tubules.

各种转运体、通道、泵在肾脏物质转运中起着重要作用。这些分子在肾脏中的精确定位和功能尚未确定。本研究分析了糖转运蛋白和有机阳离子转运蛋白在大鼠肾脏中的定位。果糖转运蛋白GLUT 5主要集中在外髓外条近端小管S3段的顶端质膜上。胰岛素募集糖转运蛋白GLUT 4在亨利氏袢细胞中表达。它定位于细胞内，特别是在高尔基体区域，包括trans-Golgi网络。此外，它定位于内体。在表达绿色荧光蛋白（GFP）标记的GLUT 4的3 T3-L1细胞中，通过活细胞的延时显微镜分析细胞中GLUT 4的动态。GLUT 4-GFP集中在核周区域。GFP-GLUT 4在高尔基体区域出现分支和融合。GFP-GLUT 4囊泡分散在细胞质中，观察到三种类型的运动：一种是不动的，保持在同一位置。第二类囊泡沿着直线快速移动较长距离。第三种，则是移动，迅速改变方向。有机阳离子转运体rOCT 1和rOCT 2在肾脏中表达，免疫荧光技术显示了它们的定位。rOCT 1定位于皮质中的旋绕近端小管中，而rOCT 2是外髓质的外条纹中的直近端小管。这两种转运蛋白定位于沿着基底侧质膜，表明它们在近端小管中的有机阳离子转移中的作用。