FIGURE 3: Regulation of glucose transporter endocytosis by nutrient stress. Under conditions of abundant glucose the adaptor protein TXNIP promotes the endocytosis of GLUT1 to restrict glucose uptake. When glucose levels decline, AMPK activation triggers the degradation of TXNIP, thereby downregulating GLUT1 endocytosis to promote glucose uptake (see section ”Glucose and energy deprivation” for further details).