正常人肌肉中GLUT1、GLUT3和GLUT4 mRNA的比较及其蛋白质的亚细胞分布

Comparison of GLUT1, GLUT3, and GLUT4 mRNA and the subcellular distribution of their proteins in normal human muscle.

作者信息

Stuart C A, Wen G, Gustafson W C, Thompson E A

机构信息

Department of Internal Medicine, The University of Texas Medical Branch at Galveston, 77555-1060, USA.

出版信息

Metabolism. 2000 Dec;49(12):1604-9. doi: 10.1053/meta.2000.18559.

DOI:10.1053/meta.2000.18559

PMID:11145124

Abstract

Basal, "insulin-independent" glucose uptake into skeletal muscle is provided by glucose transporters positioned at the plasma membrane. The relative amount of the three glucose transporters expressed in muscle has not been previously quantified. Using a combination of qualitative and quantitative ribonuclease protection assay (RPA) methods, we found in normal human muscle that GLUT1, GLUT3, and GLUT4 mRNA were expressed at 90 +/- 10, 46 +/- 4, and 156 +/- 12 copies/ng RNA, respectively. Muscle was fractionated by DNase digestion and differential sedimentation into membrane fractions enriched in plasma membranes (PM) or low-density microsomes (LDM). GLUT1 and GLUT4 proteins were distributed 57% to 67% in LDM, whereas GLUT3 protein was at least 88% in the PM-enriched fractions. These data suggest that basal glucose uptake into resting human muscle could be provided in part by each of these three isoforms.

摘要

基础状态下，进入骨骼肌的“不依赖胰岛素”的葡萄糖摄取是由位于质膜上的葡萄糖转运体提供的。此前尚未对肌肉中表达的三种葡萄糖转运体的相对含量进行定量。通过结合定性和定量核糖核酸酶保护分析（RPA）方法，我们发现在正常人体肌肉中，GLUT1、GLUT3和GLUT4 mRNA分别以90±10、46±4和156±12拷贝/ng RNA的水平表达。通过DNA酶消化和差速沉降将肌肉分级分离成富含质膜（PM）或低密度微粒体（LDM）的膜组分。GLUT1和GLUT4蛋白在LDM中的分布为57%至67%，而GLUT3蛋白在富含PM的组分中至少占88%。这些数据表明，静息人体肌肉的基础葡萄糖摄取可能部分由这三种异构体中的每一种提供。