Glucose transporter 1 , also known as solute carrier family 2, facilitated glucose transporter member 1 , is a uniporter protein that in humans is encoded by the SLC2A1 gene. GLUT1 facilitates the transport of glucose across the plasma membranes of mammalian cells. This gene encodes a facilitative glucose transporter that is highly expressed in erythrocytes and endothelial cells, including cells of the blood–brain barrier. The encoded protein is found primarily in the cell membrane and on the cell surface, where it can also function as a receptor for human T-cell leukemia virus I and II. GLUT1 accounts for 2 percent of the protein in the plasma membrane of erythrocytes.