Expression of SFT (stimulator of Fe transport) is enhanced by iron chelation in HeLa cells and by hemochromatosis in liver

SFT (stimulator of Fe transport) is a novel transport protein that has been found to facilitate uptake of iron presented to cells as either Fe(II) or Fe(III). When HeLa cells are exposed to the iron chelator desferrioxamine, levels of SFT mRNA increase in an actinomycin D-sensitive manner. In contra st, cells exposed to high levels of iron down-regulate SFT expression in a time-dependent and reversible fashion. Thus, homeostatic regulation of SFT expression not only ensures that sufficient levels of iron are maintained b ut also limits excessive assimilation to prevent potentially harmful effect s of this toxic metal. The unexpected observation that SFT transcript level s are up-regulated in hemochromatosis patients therefore suggests that enha nced SFT expression contributes to the etiology of this iron overload disor der.