Transferrin receptor-2, TfR2 or TFR2 of 801 aas and 1 TMS.  TFR2, is predominantly expressed in hepatocytes and erythroid precursor cells. In the liver, TFR2 forms a complex with HFE, a hereditary hemochromatosis-associated protein, and acts as an iron sensor. In mice, hepatocyte-specific knockout of the TFR2 gene has been shown to cause systemic iron-overload with decreased expression of hepcidin, the central regulator of iron homeostasis. In erythroid cells, TFR2 forms a complex with the erythropoietin receptor and facilitates its trafficking to the cell membrane. Hematopoietic cell-specific knockout of the TFR2 gene causes microcytic erythrocytosis in mice (Kawabata et al. 2016).