Cellular distribution and regulation of intestinal SGLT1

Abstract

Diabetes is achieving epidemic proportions in many countries. In addiction to high blood glucose it is associated with increased intestinal expression of the sodium-glucose cotransporter (SGLT1). This transporter is located in brush-border membrane (BBM) of the enterocytes and is responsible for transporting glucose and galactose from the intestinal lumen into the cytosol, using the inward Na+ gradient maintained by the basolateral Na+/K+-ATPase. Our previous results show that the adaptive response to increase dietary carbohydrates also involves increased intestinal expression of SGLT1 at the BBM. This raise does not seem to reflect changes in mRNA suggesting an involvement of posttranscriptional mechanisms in SGLT1 BBM expression. In Caco-2 cells, the intracellular SGLT1 resides in endosomes and the abundance of the transporter at BBM seems to be affected by the cellular endocytic pathway. Currently, we are focusing our studies on the regulation by glucose, insulin and other dietary factors on the cellular distribution of SGLT1 and the mechanisms of its traffick to the plasma membrane in Caco-2 cells. Acknowledgements: FCT supported CMS (SFRH/BD/42566/2007), as well as the work (POCI/AGR/62040/2004).