Transferrin receptor 1 (TfR1) and Transferrin (TfR1 (for receptor), TF (for protein))

The transferrin pathway consists of transferrin, a glycoprotein produced in the liver, which binds and transports iron through the blood to cells. Cellular uptake of iron occurs when transferrin interacts with transferrin receptor 1 (TfR1) on cell surfaces, starting receptor-mediated endocytosis. In the acidic environment of the endosome, transferrin releases iron, which is then utilized or stored by the cell. Iron-free transferrin (apotransferrin) is recycled to the plasma to begin another transport cycle. This system maintains iron homeostasis, supports cellular metabolism, and contributes to immunity by limiting iron availability to pathogens. Dysregulation is associated with anemia, cancer, infection, and other diseases.

Other names

TransferrinSerotransferrinTFApotransferrin (iron-free form)Ovotransferrin (in egg white)Transferrin receptor 1TfR1CD71

Drugs may block or mimic transferrin binding to TfR1 to inhibit iron uptake by cancer cells or microorganisms. Chelators remove iron, reducing transferrin’s ability to deliver iron. ADCs targeting TfR1 deliver cytotoxic agents into cancer cells via receptor-mediated endocytosis.