Glucose transporter 3?(or?GLUT3), also known as?solute carrier family 2, facilitated glucose transporter member 3?(SLC2A3) is a?protein?that in humans is encoded by the?SLC2A3?gene. GLUT3?facilitates?the transport ofglucose?across the?plasma membranes?of mammalian cells. GLUT3 is most known for its specific expression in?neurons?and has originally been designated as the neuronal GLUT. GLUT3 has been studied in other cell types with specific glucose requirements, including?sperm, preimplantation?embryos, circulating?white blood cells?and?carcinoma?cell lines. GLUT3 has both a higher affinity for glucose and at least a fivefold greater transport capacity than GLUT1, GLUT2 and GLUT4, which is particularly significant for its role in neuronal glucose transport, where ambient glucose levels are fivefold lower than in serum.