A gene on chromosome 3q26.2-q27 that encodes glucose transporter type 2, a plasma membrane glycoprotein of the liver, islet beta cells, intestine and kidney epithelium, which mediates facilitated bidirectional glucose transport.
One mechanism by which A1 beta-casein may contribute to the development of DM-1 relates to the potential molecular mimicry (or cross-reactivity) between beta-casein and an epitope of the pancreatic beta-cell glucose transporter GLUT2, as autoantibodies to GFUT2 have been described in patients with recent-onset DM-1.
In addition to being the major regulator of the insulin gene, Pdx1 also regulates the expression of additional islet-specific genes through its interaction with their promoter regions, which include GLUT2, Nkx6.
Then, the accumulated glucose in the enterocytes is transported by GLUT2 (Glucose Transporter 2) located in the basolateral membrane into the blood (Wood and Trayhurn, 2003) with the aid of facilitative diffusion down its concentration gradient.
Fructose absorption by the apical transporter GLUTS requires a concentration gradient, which is maintained both by the active absorption of nutrients and water and by fructose transport out of the enterocytes by the basolateral transporter GLUT2.