Transferrin receptor protein 1 (TfR1) (TfR1)

Transferrin receptor protein 1 (TfR1), also known as CD71, is the primary molecular gateway for iron uptake in human cells, mediating the internalization of iron-loaded transferrin from the circulation via receptor-mediated endocytosis. Iron is an essential cofactor for critical metabolic processes including mitochondrial respiration, DNA synthesis, and oxygen transport, making its regulated acquisition vital for cellular survival [4, 7, 15]. Because rapidly proliferating cells, such as those in malignant tumors, exhibit a disproportionately high demand for iron, TfR1 is frequently overexpressed in various cancers, serving as both a diagnostic biomarker and a target for antibody-drug conjugates (ADCs) and imaging agents [3, 5, 17]. Beyond its role in oncology, the iron uptake process is strictly regulated to prevent the toxicity of free iron, and its dysregulation is central to the pathogenesis of iron-deficiency anemia and iron overload disorders like hereditary hemochromatosis [7, 15]. Pharmacological interventions targeting this system include monoclonal antibodies that block transferrin binding, iron chelators that deplete the labile iron pool, and 'Trojan horse' delivery systems designed to bypass physiological barriers like the blood-brain barrier [3, 12]. Additionally, in microbiology, specialized iron uptake machineries such as bacterial siderophore receptors and the TonB system represent high-value targets for novel antibiotics designed to deprive pathogens of this essential nutrient [8, 11, 12].

Other names

TFRCCD71TFR1p90Transferrin receptor protein 1TRFRIron uptake pathwaySiderophore-mediated iron uptake

Drugs target the iron uptake system through several mechanisms: direct competitive inhibition of holo-transferrin binding to the receptor; utilization of the receptor-mediated endocytosis pathway to deliver cytotoxic payloads or enzymes across the blood-brain barrier; and the use of chelating agents to sequester iron, thereby preventing its metabolic utilization and inducing iron starvation in target cells [3, 7, 12].