title: Floating cholera toxin into epithelial cells: functional association with caveolae-like detergent-insoluble membrane microdomains.
abstract: In polarized cells, signal transduction by cholera toxin (CT) requires apical endocytosis and retrograde transport into Golgi cisternae and likely endoplasmic reticulum (ER) (Lencer et al., J. Cell Biol. 131, 951-962 (1995)). We have recently found that the toxin's apical membrane receptor ganglioside GM1 acts specifically in this signal transduction pathway, likely by coupling CT with caveolae or caveolae-related membrane domains (lipid rafts) (Wolf et al., J. Cell Biol. 141, 917-927 (1998)). Work in progress shows that 1) cholesterol depletion uncouples the CT-GM1 receptor complex from signal transduction, a characteristic of lipid rafts; 2) the GM1 acyl chains rather than the carbohydrate head groups appear to account for the structural basis of ganglioside specificity in toxin trafficking; and 3) intestinal epithelial cells obtained from normal adult humans exhibit lipid rafts which differentiate between CT-GM1 and LTIIb-GD1a complexes and which contain caveolin 1.
authors: GI Cell Biology, Children's Hospital, Department of Pediatrics, Harvard Medical School, Harvard Digestive Diseases Center, Boston, MA 02115, USA.
authors: K
authors: K
authors: Badizadegan
authors: A A
authors: AA
authors: Wolf
authors: C
authors: C
authors: Rodighiero
authors: M
authors: M
authors: Jobling
authors: T R
authors: TR
authors: Hirst
authors: R K
authors: RK
authors: Holmes
authors: W I
authors: WI
authors: Lencer
mesh_terms: D000818:Animals; D021941:Caveolae / Q000378:metabolism*; D002772:Cholera Toxin / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D005677:G(M1) Ganglioside / Q000378:metabolism; D006801:Humans; D021122:Protein Subunits; D015398:Signal Transduction
chemical_list: D003902:Detergents; D021122:Protein Subunits; D005677:G(M1) Ganglioside; D002772:Cholera Toxin