Characterization of a putative receptor for intestinal trefoil factor in rat small intestine: identification by in situ binding and ligand blotting.

Intestinal trefoil factor (ITF), a small peptide secreted by intestinal goblet cells, maintains mucosal integrity and promotes epithelial wound healing. Although ITF has been cloned, the detailed mechanism by which ITF interacts with intestinal epithelium remains elusive. In the present study, we expressed mature rat ITF (rITF) with pXa (a prokaryotic expression vector) in Escherichia coli to generate a biotinylated rITF fusion protein (bTag-ITF). By using bTag-ITF probe, we identified ITF binding cells in the crypts of the small intestine and mucous cells of the region of gastric glands. Using a ligand blotting technique, we further characterized a 50 kDa glycosylated protein from the membrane fraction of the small intestine, which bound to bTag-ITF. Our data suggest that this 50 kDa membrane glycoprotein is a putative receptor for ITF in the gastrointestinal tract.