Activators of AMP-activated protein kinase enhance GLUT4 translocation and its glucose transport activity in 3T3-L1 adipocytes
Activators of AMP-activated protein kinase enhance GLUT4 translocation and its glucose transport activity in 3T3-L1 adipocytes
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DOI：
10.1152/ajpendo.00456.2004
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发表时间：
2005-10-01
影响因子：
5.1
通讯作者：
Ishida, H
中科院分区：
文献类型：
--
作者：
Yamaguchi, S;Katahira, H;Ishida, H
为了确定腺苷酸活化蛋白激酶（AMPK）激活后脂肪细胞葡萄糖摄取的增加是否是由GLUT 4加速转位到质膜介导的，我们构建了GLUT 4和增强型绿色荧光蛋白（GLUT 4-eGFP）的嵌合体，并将其cDNA转移到3 T3-L1脂肪细胞的细胞核中。然后，通过激光扫描共聚焦显微镜在活细胞中观察GLUT 4-eGFP易位的动力学。结果表明，5-氨基咪唑-4-甲酰胺-1-β-D-呋喃核糖苷（AICAR）和2，4-二硝基苯酚（DNP），已知的AMPK激活剂的刺激，迅速加速其易位在4分钟内，在胰岛素刺激的情况下发现。Wortmannin可明显抑制胰岛素诱导的GLUT 4转位（P < 0.01）。然而，通过AMPK激活剂AICAR和DNP的GLUT 4易位不受渥曼青霉素的影响。SB-203580（一种p38丝裂原活化蛋白激酶（MAPK）抑制剂）不抑制胰岛素和AMPK激活的GLUT 4易位。添加AMPK激活剂AICAR和DNP后，葡萄糖摄取显著增加（P < 0.05）。wortmannin对AMPK和胰岛素刺激的葡萄糖摄取有相似的抑制作用（P < 0.05 ~ 0.01）。SB-203580还能显著抑制AMPK和胰岛素诱导的葡萄糖摄取增加（P < 0.05）。这些结果表明，AMPK激活的3 T3-L1脂肪细胞中的GLUT 4易位是通过激活的磷脂酰肌醇3-激酶位点远端的胰岛素信号通路或通过不同于胰岛素激活的信号系统介导的。另一方面，依赖于AMPK激活剂AICAR和DNP的葡萄糖摄取的增加将另外归因于易位的GLUT 4蛋白的内在活性的增强，可能通过p38 MAPK依赖性机制。
To determine whether the increase in glucose uptake following AMP-activated protein kinase ( AMPK) activation in adipocytes is mediated by accelerated GLUT4 translocation into plasma membrane, we constructed a chimera between GLUT4 and enhanced green fluorescent protein ( GLUT4-eGFP) and transferred its cDNA into the nucleus of 3T3-L1 adipocytes. Then, the dynamics of GLUT4-eGFP translocation were visualized in living cells by means of laser scanning confocal microscopy. It was revealed that the stimulation with 5-aminoimidazole-4-carboxamide-1-beta-D- ribofuranoside ( AICAR) and 2,4-dinitrophenol (DNP), known activators of AMPK, promptly accelerates its translocation within 4 min, as was found in the case of insulin stimulation. The insulin-induced GLUT4 translocation was markedly inhibited after addition of wortmannin ( P < 0.01). However, the GLUT4 translocation through AMPK activators AICAR and DNP was not affected by wortmannin. Insulin- and AMPK-activated translocation of GLUT4 was not inhibited by SB-203580, an inhibitor of p38 mitogen-activated protein kinase ( MAPK). Glucose uptake was significantly increased after addition of AMPK activators AICAR and DNP ( P < 0.05). AMPK- and insulin-stimulated glucose uptake were similarly suppressed by wortmannin ( P < 0.05 - 0.01). In addition, SB-203580 also significantly prevented the enhancement of glucose uptake induced by AMPK and insulin ( P < 0.05). These results suggest that AMPK- activated GLUT4 translocation in 3T3-L1 adipocytes is mediated through the insulin-signaling pathway distal to the site of activated phosphatidylinositol 3-kinase or through a signaling system distinct from that activated by insulin. On the other hand, the increase of glucose uptake dependent on AMPK activators AICAR and DNP would be additionally due to enhancement of the intrinsic activity in translocated GLUT4 protein, possibly through a p38 MAPK-dependent mechanism.