title: INF-gamma rearranges membrane topography of MHC-I and ICAM-1 in colon carcinoma cells.
abstract: Flow-cytometric fluorescence energy transfer (FCET) measurements between fluorescently labeled cell surface MHC-I and ICAM-1 molecules indicated similar receptor patterns in the plasma membrane of interferon-gamma (INF-gamma)-treated colon carcinoma cells as those observed earlier at the surface of lymphoid cells. INF-gamma activation significantly increased the density of MHC-I and ICAM-1 proteins in the membrane. This increase in receptor density was accompanied by decreased proximity level of the homo-associated MHC-I receptors. Hetero-association of MHC-I and ICAM-1 molecules was increased by INF-gamma treatment. INF-gamma changed neither hetero- nor homo-association of transferrin receptors. By staining the sphingomyelin/cholesterol-enriched lipid microdomains with fluorescently labeled cholera toxin B subunit, we found an increase in the amount of lipid-raft associated G(M1)-gangliosides due to INF-gamma treatment. Confocal microscopic results and FCET measurements show that MHC-I and ICAM-1 are components of G(M1)-ganglioside containing lipid-rafts and also support an increase in the size of these lipid-rafts upon INF-gamma treatment.
authors.affiliation: Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Bacsó
authors.forename: László
authors.initials: L
authors.lastname: Bene
authors.forename: László
authors.initials: L
authors.lastname: Damjanovich
authors.forename: Sándor
authors.initials: S
authors.lastname: Damjanovich
mesh_terms: D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D002462:Cell Membrane / Q000187:drug effects*; D002772:Cholera Toxin / Q000737:chemistry / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005677:G(M1) Ganglioside / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology*; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D018613:Microscopy, Confocal; D011485:Protein Binding / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D015395:Histocompatibility Antigens Class I; D011956:Receptors, Cell Surface; D011990:Receptors, Transferrin; D018799:Intercellular Adhesion Molecule-1; D005677:G(M1) Ganglioside; D007371:Interferon-gamma; D002772:Cholera Toxin; D016650:Fluorescein-5-isothiocyanate