Abstract
In mammals the uptake and maintenance of glucose in plasma is achieved in part by the action of specific glucose transporters. These are of two types: the sodium-dependent glucose transporters (SGLTs) which actively transport glucose against its concentration gradient by coupling with Na+; and the facilitated glucose transporters (GLUTs) which operate by facilitated diffusion. These transporters have been suggested to play roles in differentiation, tumorigenesis and development of several diseases, including diabetes, but the mechanisms underlying these processes are unclear. The use of molecular biological techniques, which began with the cloning of the cDNA of erythroid-type glucose transporter (GLUT-1) in 1985, has resulted in the cloning of five isoforms of GLUTs and of an SGLT within 5 years, and much has been learned about their chromosomal locations and amino acid sequences as well as how these molecules are oriented in the plasma membrane. These exciting advances provide a new dimension to the study of regulation mechanism of of glucose transport at the molecular level.
