GLUT1

Facilitated Glucose Transporter 1, Solute Carrier Family 2, Homo sapiens

spinqualitylabelsall models Crystal structure 4PYP from PDB Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Function The GLUT1 is an insulin-independent glucose transporter expressed by all cells in the body to maintain adequate baseline glucose uptake. Tissues that express GLUT1 at high concentrations include (but are not limited to): the placenta and fetal tissues, epithelial cells of the retina and mammary gland, and the brain. Brain The GLUT1 transporter works synergistically with other solute carriers in the brain. Astrocytes and endothelial cells of brain capillaries primarily express GLUT1; neurons primarily express Glut3. GLUT1 has a relatively high Km and is upregulated in times of hypoglycemia in the brain to ensure adequate glucose uptake. Glut3 has a low Km to ensure a steady supply of glucose for neurons even when extracellular glucose concentrations are low. Pregnancy The GLUT1 transporter is highly expressed in both the placenta and the developing embryo/fetus. During pregnancy, there is no significant fetal gluconeogenesis in humans. High GLUT1 expression in the fetoplacental tissues ensures that the fetus receives a steady supply of glucose. Retina Studies on mice have shown that GLUT1 knockout leads to photoreceptor cell death; cone cells are less affected than rod cells. Disease Cancer Oncogenes such as Ras and Src have been linked to upregulation of GLUT1 in rat tumors. Many studies have shown that GLUT1 is upregulated in malignancies of the breast. Upregulation of the GLUT1 transporter has been shown to increase cell proliferation in some types of breast cancer. Structural highlights The GLUT1 transporter has one known N-linked glycosylation site at Asn 45 and varied molecular weights of the GLUT1 transporter suggest glycosylation is dependent on cell type. This glycosylation site is thought to be important for glucose binding to the extracellular portion of the transporter. Mutations in the GLUT1 transporter from Asn 45 to an Asp, Tyr, or Gln residue have been shown to increase the Km of the enzyme. GLUT1 has a hydrophobic pocket

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