title: The impact of N- and O-glycosylation on the functions of Glut-1 transporter in human thyroid anaplastic cells.
abstract: It has been previously shown that glucose transporter Glut-1 expression was detectable by immunostaining in tissue sections from anaplastic carcinoma, but not in normal thyroid tissue. Using human thyroid anaplastic carcinoma cells, we studied the mechanism by which Glut-1 molecules are translocated from the endoplasmic reticulum to the cell surface. The contribution of N- and O-linked glycans for the translocation and activity of Glut-1 transporter is emphasized. The inhibition of N-glycosylation with tunicamycin (TM) led to a 50% decrease in glucose transport while glycosylated and unglycosylated forms of Glut-1 were found at the cell surface. However, the inhibition of N-linked oligosaccharide processing with deoxymannojirimycin (dMJ) and swainsonine (SW) influenced neither the intracellular trafficking nor the activity of the transporter. On the other hand, Glut-1 bound to the O-linked glycan-specific lectin jacalin and the O-glycosylation inhibitor benzyl-N-acetylgalactosamine dramatically inhibited glucose transport. These results show that O- and N-linked oligosaccharides arbored by Glut-1 are essential for glucose transport in anaplastic carcinoma cells. The quantitative and qualitative alterations of Glut-1 glycosylation and the increase in glucose transport are associated with the anaplastic phenotype of human thyroid cells.
authors.affiliation: INSERM U-559, Faculté de Médecine, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Cedex 5, Marseilles, France.
authors.forename: Nezha
authors.initials: N
authors.lastname: Samih
authors.forename: Sonia
authors.initials: S
authors.lastname: Hovsepian
authors.forename: Frédéric
authors.initials: F
authors.lastname: Notel
authors.forename: Maëlle
authors.initials: M
authors.lastname: Prorok
authors.forename: Hélène
authors.initials: H
authors.lastname: Zattara-Cannoni
authors.forename: Sylvie
authors.initials: S
authors.lastname: Mathieu
authors.forename: Dominique
authors.initials: D
authors.lastname: Lombardo
authors.forename: Guy
authors.initials: G
authors.lastname: Fayet
authors.forename: Assou
authors.initials: A
authors.lastname: El-Battari
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001665:Binding Sites; D019921:Biotinylation; D015153:Blotting, Western; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1; D006026:Glycoside Hydrolases; D006031:Glycosylation; D006801:Humans; D007621:Karyotyping; D008361:Mannosidases / Q000037:antagonists & inhibitors; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D013964:Thyroid Neoplasms; D014407:Tumor Cells, Cultured; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D051272:Glucose Transporter Type 1; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; C495677:SLC2A1 protein, human; D014415:Tunicamycin; D006026:Glycoside Hydrolases; D008361:Mannosidases; D005947:Glucose; D009584:Nitrogen; D010100:Oxygen