Characterization of a glycoprotein expressed on the basolateral membrane of human intestinal epithelial cells and cultured colonic cell lines.

A protein from the basolateral domain of adult human intestinal epithelial cells has been identified and characterized by the monoclonal antibody technique in combination with immunocytochemical and biochemical methods. The protein is found preferentially on the lateral surface of the cells. Extraction of intestinal membranes with Triton X-114 or their treatment with hydrolases indicated that the protein is an integral membrane glycoprotein of apparent molecular weight 38 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In the adult this protein is restricted to intestine, pancreas and gallbladder, consistent with their common embryonic origin. It was also expressed in the intestine of a 24-week-old human embryo and was found as a basolateral marker in cultured cell lines originating from human colonic adenocarcinomas.