The transferrin receptor

This chapter discusses the structure and function of transferrin receptor (TfR). It also discusses the role of TfR in cell proliferation, TfR as a diagnostic marker of disease, and heterogeneity of the TfR and TfR in other organisms. The transferrin receptor (TfR) is an excellent model system to study ligand–receptor interactions and receptor-mediated endocytosis, as well as being important in the delivery of iron to cells. Iron is essential to many processes within the cell. Transferrin (Tf) is the major iron-transport protein in the blood of a wide variety of vertebrates and invertebrates. The uptake of Tf into cells that are rapidly proliferating or that have a specialized requirement for iron is mediated by a specific plasma membrane receptor—the TfR. The TfR gene is 31 Kb and contains at least 19 introns. The mRNA is 4.9 Kb, 2.3 Kb of which codes for the TfR and the remaining 2.5 Kb is the 3' untranslated region. Chromosome mapping of the TfR revealed that it is located on human chromosome 3. More detailed mapping indicated that it is located on q26.2→qter. Two other iron proteins, Tf and p97, are also located on chromosome 3 in the same region.