TRANSLOCATION OF THE GLUCOSE TRANSPORTER GLUT4 IN CARDIAC MYOCYTES OF THE RAT
TRANSLOCATION OF THE GLUCOSE TRANSPORTER GLUT4 IN CARDIAC MYOCYTES OF THE RAT
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DOI：
10.1073/pnas.88.17.7815
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发表时间：
1991-09-01
影响因子：
11.1
通讯作者：
LIENHARD, GE
中科院分区：
文献类型：
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作者：
SLOT, JW;GEUZE, HJ;LIENHARD, GE
胰岛素调节的葡萄糖转运蛋白GLUT 4免疫定位在大鼠心肌的基础和刺激的葡萄糖摄取的条件下，分别通过禁食和运动/胰岛素刺激相结合。在基底肌细胞中，在质膜的不同区域（肌膜、闰盘和横管系统）中存在非常少（<1%）的GLUT 4。GLUT 4定位于小管囊泡元件，主要发生在肌膜和横管系统附近和trans-Golgi区域。在刺激后，在质膜中发现几乎等于42%的GLUT 4。质膜的每个域对这种效应的贡献相等。GLUT 4阳性，网格蛋白包被的小坑也存在于每个细胞表面域。其余的标记是在管状泡状元素在相同的网站在基底细胞和闰盘地区。GLUT 4在心肌细胞中的定位与在棕色脂肪细胞、骨骼肌和白色脂肪细胞中的定位基本相同。我们的结论是，增加葡萄糖在肌肉和脂肪中的转运占GLUT 4从细胞内的小管囊泡元件的质膜易位。包被凹坑的标记表明，在刺激的肌细胞，在脂肪细胞，GLUT 4不断之间的内体室和质膜和胞吐速率常数的刺激，可能是GLUT 4易位的主要机制。
The insulin-regulated glucose transporter GLUT4 was immunolocalized in rat cardiac muscle under conditions of basal and stimulated glucose uptake, achieved by fasting and a combined exercise/insulin stimulus, respectively. In basal myocytes there was very little (< 1 %) GLUT4 in the different domains of the plasma membrane (sarcolemma, intercalated disk, and transverse tubular system). GLUT4 was localized in small tubulo-vesicular elements that occur predominantly near the sarcolemma and the transverse tubular system and in the trans-Golgi region. Upon stimulation almost-equal-to 42% of GLUT4 was found in the plasma membrane. Each domain of the plasma membrane contributed equally to this effect. GLUT4-positive, clathrin-coated pits were also present at each cell surface domain. The remainder of the labeling was in tubulo-vesicular elements at the same sites as in basal cells and in the intercalated disk areas. The localization of GLUT4 in cardiac myocytes is essentially the same as in brown adipocytes, skeletal muscle, and white adipocytes. We conclude that increased glucose transport in muscle and fat is accounted for by translocation of GLUT4 from the intracellular tubulo-vesicular elements to the plasma membrane. The labeling of coated pits indicates that in stimulated myocytes, as in adipocytes, GLUT4 recycles constantly between the endosomal compartment and the plasma membrane and that stimulation of the exocytotic rate constant is likely the major mechanism for GLUT4 translocation.