Most mammalian cells transport glucose through a family of membrane proteins known as glucose transporters. Molecular cloning of these glucose transporters has identified a family of closely related genes that encodes at least 7 proteins (Glut-1 to Glut-13, MW:40-80kD) and Sodium glucose co-transporter-1 (SGLT-1, 662 amino acids; ~75kD). Individual member of this family have identical predicted secondary structures with 12 transmembrane domains. Both N and C-termini are predicted to be cytoplasmic. Most differences in sequence homology exist within the four hydrophilic domains that may play a role in tissue-specific targeting. Glut isoforms differ in their tissue expression, substrate specificity and kinetic characteristics. Glut-1 mediates glucose transport into red cells, and throughout the blood brain barrier, and supply glucose to most cells. Glut-2 provides glucose to the liver and pancreatic cells. Glut-3 is the main transporter in neurons, whereas Glut-4 is primarily expressed in muscle and adipose tissue and regulated by insulin.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.