GLUT1
One specific form of transport that plays a key role in the metabolism of many organisms is that of glucose. It involves membrane bound glucose transporters (GLUT or SLC2A) and sodium-dependent glucose co-transporters (or sodium-glucose linked transporters, SGLT). The latter (SGLT), for example, is a protein highly abundant in kidneys, that serves renal glucose reabsorption, and therefore is of high interest as a target for the treatment of diabetes[1] (for example SGLT2 inhibitor Remogliflozin (Axon 1634)). SGLTs are secondary-active cell-membrane co-transporters, driven by the Na+/K+-ATPase pump, which actively extrudes sodium across the basolateral membrane, in conjunction with the inward transfer of specific hexose sugars or some other molecules against their concentration gradient from the small intestine and kidney (SGLT1 and SGLT2 respectively). SGLTs should not be confused with facilitated glucose transporters (GLUTs) that mediate passive transfer of glucose across cell membranes down a concentration gradient. However, as in both the intestine and kidney, the two different types of transporters can operate in tandem: SGLTs transfer glucose into the cell across the luminal membrane whereas GLUTs transfer glucose out of the cell across the basolateral membrane[2].
[1] Remogliflozin etabonate, in a Novel Category of Selective Low-Affinity / High-Capacity Sodium Glucose Cotransporter (SGLT2) Inhibitors, Exhibits Antidiabetic Efficacy in Rodent Models. Y. Fujimori, K. Katsuno,I. Nakashima, Y. Ishikawa-Takemura, H. Fujikura, M. Isaji. J. Pharmacol. Exp. Ther. 2008, 327, 268–276.
[2] A.A. Tahrani et al. SGLT inhibitors in management of diabetes. Lancet Diab. Endocrin. 2013, 1, 140-151.