title: Ability of blood group A-active glycosphingolipids to act as Escherichia coli heat-labile enterotoxin receptors in HT-29 cells.
abstract: We examined the ability of blood group A-active glycoconjugates to act as receptors for Escherichia coli heat-labile type I enterotoxin (LT-I) in HT-29 cells. These cells contained ~4 times more specific binding sites for LT-I than for cholera toxin (CT). Binding of LT-I could not be blocked by the B subunit of CT (CT-B), indicating the existence of LT-I receptors in addition to the glycosphingolipid GM1. LT-I was able to increase levels of cyclic adenosine monophosphate (AMP), even in the presence of CT-B. Helix pomatia and anti-blood group A antibody caused a dose-dependent inhibition of binding of LT-I to cells and production of cyclic AMP. LT-I recognized several complex blood group A-active glycosphingolipids from cells, and this interaction was also interfered with by H. pomatia. Treatment of cells with D,L-threo-1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol diminished surface expression of blood group A-active glycosphingolipids and binding of LT-I to non-GM1 receptors. These observations suggest that blood group A-active glycosphingolipids can function as alternative receptors for LT-I in HT-29 cells.
authors.affiliation: Departamento de Quimica Biológica, "Dr. Ranwel Caputto"-Centro de Investigaciones en Química Biológica de Córdoba, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
authors.forename: Estela M
authors.initials: EM
authors.lastname: Galván
authors.forename: Claudio D
authors.initials: CD
authors.lastname: Diema
authors.forename: German A
authors.initials: GA
authors.lastname: Roth
authors.forename: Clara G
authors.initials: CG
authors.lastname: Monferran
mesh_terms: D000017:ABO Blood-Group System / Q000737:chemistry*; D001427:Bacterial Toxins / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004768:Enterotoxins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006028:Glycosphingolipids / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D008024:Ligands; D008614:Meperidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000017:ABO Blood-Group System; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D006028:Glycosphingolipids; D008024:Ligands; D018000:Receptors, Peptide; C026733:4-propionyloxy-4-phenyl-N-methylpiperidine; D008614:Meperidine; C027538:heat-labile enterotoxin, E coli; D000242:Cyclic AMP; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled