Immunocytochemical detection of GLUT2 at the rat intestinal brush-border membrane.
We have proposed a new model of intestinal sugar absorption in which high sugar concentrations promote rapid insertion of the facilitative transporter GLUT2 into the brush-border membrane so that absorptive capacity is precisely regulated to match dietary intake during the assimilation of a meal. However, location of GLUT2 at the brush border by immunocytochemistry has been problematical. We report that control of rapid GLUT2 trafficking and the use of an antibody to a sequence within the large extracellular loop of GLUT2 permits localization of GLUT2 at the brush border. To reveal brush-border GLUT2 fully, it is necessary to digest the sugar chain at the glycosylation site close to the antigenic site. In this way, we have demonstrated by immunocytochemistry PKC-dependent changes in the regulation of brush-border GLUT2 in rat jejunum that correspond to those seen by Western blotting. The functional and immunocytochemical data are now reconciled.
Affleck
Julie A
JA
Department of Biology, University of York, York YO10 5YW, United Kingdom.
Helliwell
Philip A
PA
Kellett
George L
GL
D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D001692:Biological Transport; D020536:Enzyme Activators / Q000494:pharmacology; D005632:Fructose / Q000378:metabolism; D051273:Glucose Transporter Type 2; D007150:Immunohistochemistry; D007583:Jejunum / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis*; D010617:Phenanthridines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000470:Alkaloids; D053119:Benzophenanthridines; D020536:Enzyme Activators; D051273:Glucose Transporter Type 2; D009004:Monosaccharide Transport Proteins; D010617:Phenanthridines; D005632:Fructose; C016299:chelerythrine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate