title: Overexpression of HFE in HepG2 cells reveals differences in intracellular distribution and co-localization of wt- and mutated forms.
abstract: Liver is the primary target organ of Hereditary Hemochromatosis Type I, with the HFE mutations C282Y and H63D recognized as markers of this iron-overload disease. Hepatocytes are also the main site of synthesis of HFE. However, most early studies of overexpression of HFE were done in non-hepatic, non-HFE-expressing, cell lines. Here we report the setting up of a stable transfection model of wt- and mutant-HFE (H63D and C282Y) proteins in a hepatic cell line (HepG2), the analysis of its intracellular distribution and the effect of diferric transferrin on HFE localization. The C282Y mutant is retained in the ER, whereas HFE-wt and H63D co-localize with TfR1 exclusively in early recycling endosomes. Holotransferrin induces a re-localization of wt- and H63D-HFE, from early recycling endosomes to the cytoplasmic membrane. In conclusion our results establish the HepG2 cell line as a valuable model for the study of HFE.
authors.affiliation: Iron Genes and Immune System, IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Jorge P
authors.initials: JP
authors.lastname: Pinto
authors.forename: Pedro
authors.initials: P
authors.lastname: Ramos
authors.forename: Maria
authors.initials: M
authors.lastname: de Sousa
mesh_terms: D019943:Amino Acid Substitution; D045744:Cell Line, Tumor; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D015870:Gene Expression; D006432:Hemochromatosis / Q000235:genetics / Q000378:metabolism*; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D021381:Protein Transport / Q000235:genetics; D014168:Transferrin / Q000378:metabolism
chemical_list: C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins; D014168:Transferrin; C028283:diferric transferrin