The role of GLUT2 in dietary sugar handling.

GLUT2 is a facilitative glucose transporter located in the plasma membrane of the liver, pancreatic, intestinal, kidney cells as well as in the portal and the hypothalamus areas. Due to its low affinity and high capacity, GLUT2 transports dietary sugars, glucose, fructose and galactose in a large range of physiological concentrations, displaying large bidirectional fluxes in and out the cells. This review focuses on the roles of GLUT2. The first identified function of GLUT2 is its capacity to fuel metabolism and to provide metabolites stimulating the transcription of glucose sensitive genes. Recently, two other functions of GLUT2 are uncovered. First, the insertion of GLUT2 into the apical membrane of enterocytes induces the acute regulation of intestinal sugar absorption after a meal. Second, the GLUT2 protein itself initiates a protein signalling pathway triggering a glucose signal from the plasma membrane to the transcription machinery.