ABSTRACT
The stimulation of glucose transport across the plasma membrane by insulin in muscle and fat tissue, the main sites of postprandial glucose utilization, is crucial to the maintenance of glucose homeostasis (1,2). The first insights into this intricately regulated membrane transport process were provided in 1980 when it was demonstrated that the stimulation of glucose transport by insulin in isolated adipocytes was accompanied by the translocation of presynthesized glucose transporters to the plasma membrane from a poorly defined intracellular locale (3,4). It was later discovered that this transporter, now referred to as glucose transporter 4 (GLUT4), constitutes the main, but not the only, insulin-responsive glucose transporter in muscle (5), fat (6), and other insulin-responsive cell lines (7,8). In addition to GLUT4, insulin recruits GLUT1, the principal mediator of basal glucose uptake, to the plasma membrane in insulin-responsive tissues and cell lines (1,2,9).
