GLUT2

Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables passive glucose movement across cell membranes. It is the principal transporter for transfer of glucose between liver and blood, and for renal glucose reabsorption. In humans, this protein is encoded by the SLC2A2 gene.

Tissue distribution
GLUT2 is found in cellular membranes of:
 * liver
 * pancreatic beta cells
 * hypothalamus
 * basolateral and brush border membrane of small intestine
 * basolateral membrane of renal tubular cells

Function
GLUT2 has high capacity for glucose but low affinity (high Km, ca. 5 mM) part of "the glucose sensor" in pancreatic β-cells. It is a very efficient carrier for glucose.

GLUT2 also carries glucosamine.

In small intestine during meals GLUT2 trafficking to the brush border membrane, enhancing the capacity of glucose transport when the luminal glucose concentration goes above 30mM.

Clinical significance
Defects in the SLC2A2 gene are associated with a particular type of glycogen storage disease called Fanconi-Bickel syndrome.

It has been proposed by genetics researchers in neonatal and maternal-fetal medicine at Harvard University Medical School and Beth-Israel Deaconess Hospital Medical Center that this creates a problem for drug-treated diabetic pregnancies in which glucose levels in the woman are uncontrolled, exposing her fetus to the possibility of neural tube and cardiac defects in the early-developing brain, spine, and heart. 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.

Maintaining a regulated osmotic balance of sugar concentration between the blood circulation and the interstitial spaces is critical in some cases of edema including cerebral edema.

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 referred to as the "diabetic glucose transporter" or a "stress hyperglycemia glucose transporter."