Fig. 1

Iron homeostasis: the transferrin-to-cell cycle. At neutral pH, apotranferrin is released at the cell membrane. The iron-transferrin complex then binds to its receptor at the cell membrane and endosomal fusion occurs. A complex is then formed with divalent metal transporter 1. At pH 5.5 iron is reduced and released to be used by the mitcochodria or stored as ferritin. The Golgi body package the apotransferrin-receptor complex into a vesicle and it is transported back to the cell membrane