Antonescu Costin N, Randhawa Varinder K, Klip Amira
Hospital for Sick Children, Toronto, Ontario, Canada.
Methods Mol Biol. 2008;457:367-78. doi: 10.1007/978-1-59745-261-8_27.
Postprandial blood glucose homeostasis is regulated by an insulin-stimulated increase in glucose transport into muscle and fat tissues via glucose transporter isoform 4 (GLUT4). In the basal state, this constitutively recycling membrane protein predominantly resides intracellularly. In order to achieve the insulin-stimulated increase in glucose flux, GLUT4 increases its cell surface abundance at the expense of preformed intracellular depots. By confocal microscopy of cultured L6 muscle cells stably expressing myc-tagged GLUT4 (L6-GLUT4myc), we can visualize the two arms of GLUT4 traffic: exocytosis (movement to the cell surface) and endocytosis (internalization from the cell surface).
餐后血糖稳态是通过胰岛素刺激，经由葡萄糖转运蛋白异构体4（GLUT4）增加葡萄糖向肌肉和脂肪组织的转运来调节的。在基础状态下，这种持续循环的膜蛋白主要位于细胞内。为了实现胰岛素刺激的葡萄糖通量增加，GLUT4以预先形成的细胞内储存库为代价增加其细胞表面丰度。通过对稳定表达myc标签的GLUT4的培养L6肌肉细胞（L6-GLUT4myc）进行共聚焦显微镜检查，我们可以观察到GLUT4转运的两个过程：胞吐作用（向细胞表面移动）和胞吞作用（从细胞表面内化）。
