Figure 10.

Model for GLUT4 trafficking in 3T3-L1 adipocytes. GLUT4 is dynamically retained within cells in the basal state because it is internalized much faster than it is exocytosed. Insulin induces GLUT4 redistribution to the plasma membrane by increasing exocytosis and inhibiting internalization. Insulin signaling to GLUT4 exocytosis requires Akt phosphorylation of the AS160 RabGAP. Insulin signaling to endocytosis does not require AS160, demonstrating divergent signaling pathways regulate these two aspects of GLUT4 trafficking.