Overexpression of HFE in HepG2 cells reveals differences in intracellular distribution and co-localization of wt- and mutated forms

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.