|solute carrier family 2 (facilitated glucose transporter), member 2|
|Locus||Chr. 3 q26.2-q27|
Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes. It is the principal transporter for transfer of glucose between liver and blood, and has a role in renal glucose reabsorption. In humans, this protein is encoded by the SLC2A2 gene. Unlike GLUT4, it does not rely on insulin for facilitated diffusion.
GLUT2 is found in cellular membranes of:
- liver (Primary)
- pancreatic β cell (Primary)
- hypothalamus (Not overly significant)
- basolateral membrane of small intestine and apical GLUT2 is also suggested.
- basolateral membrane of renal tubular cells
GLUT2 has high capacity for glucose but low affinity (high Km, ca. 15-20 mM) and thus functions as part of the "glucose sensor" in pancreatic β-cells. It is a very efficient carrier for glucose.
When the glucose concentration in the lumen of the small intestine goes above 30mM, such as occurs in the fed-state, GLUT2 is up-regulated at the brush border membrane, enhancing the capacity of glucose transport. Basolateral GLUT2 in enterocytes also aids in the transport of fructose into the bloodstream through glucose-dependent cotransport.
In drug-treated diabetic pregnancies in which glucose levels in the woman are uncontrolled, neural tube and cardiac defects in the early-developing brain, spine, and heart depend upon functional GLUT2 carriers, and defects in the Glut2 gene have been shown to be protective against such defects in rats. However, whilst a lack of GLUT2 adaptability is negative, it is important to remember the fact that the main result of untreated gestational diabetes appears to cause babies to be of above-average size, which may well be an advantage that is managed very well with a healthy GLUT2 status.
GLUT2 appears to be particularly important to osmoregulation, and preventing edema-induced stroke, transient ischemic attack or coma, especially when blood glucose concentration is above average. GLUT2 could reasonably be referred to as the "diabetic glucose transporter" or a "stress hyperglycemia glucose transporter."
Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534".
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