Model of regulation of erythroid iron intake, cell proliferation, and differentiation. Recent findings indicate that iron-related proteins, previously characterized in the liver, are expressed in erythroid precursors. Although their function is largely uncharacterized in these cells, here we speculate on their potential function. In normal conditions, HFE has the potential to influence TfR1-mediated iron intake, whereas TfR2, binding EPOR, may modulate erythropoiesis, iron metabolism, or both. Under conditions of low iron intake, TfR1 mRNA is stabilized by IRP2 and iron intake increases. Under conditions of high Tf saturation, erythroid iron intake is probably modulated by loss of IRP2 activity, limiting TfR1 synthesis. FPN may export iron to avoid iron toxicity or to further control cellular iron content in normal or other uncharacterized altered physiologic conditions. Furthermore, excess of intracellular heme, potentially toxic, may be prevented by the heme exporter FLVCR (feline leukemia virus C receptor), both under conditions of normal and abnormal erythroid iron intake.