Transferrin Receptor 1 (TFRC, also known as TfR, TfR1, or CD71) is a transmembrane glycoprotein that mediates cellular iron uptake by binding and internalizing iron-loaded transferrin. As the primary gateway for iron entry into most cells, TFRC plays a critical role in regulating iron homeostasis and is increasingly recognized for its involvement in neurodegenerative diseases characterized by iron dysregulation.[@gomme2005]
Structure and Domains
TFRC is a type II transmembrane protein that functions as a homodimer:[@cheng2004]
Domain organization:
Cytoplasmic domain (61 residues): Contains the YTRF internalization motif for clathrin-mediated endocytosis
Transmembrane domain (26 residues): Single alpha-helix anchoring the receptor
Extracellular domain (672 residues): Binds transferrin with high affinity
Dimerization interface: The functional receptor is a disulfide-linked homodimer
Transferrin Receptor 1 (TFRC, also known as TfR, TfR1, or CD71) is a transmembrane glycoprotein that mediates cellular iron uptake by binding and internalizing iron-loaded transferrin. As the primary gateway for iron entry into most cells, TFRC plays a critical role in regulating iron homeostasis and is increasingly recognized for its involvement in neurodegenerative diseases characterized by iron dysregulation.[@gomme2005]
Structure and Domains
TFRC is a type II transmembrane protein that functions as a homodimer:[@cheng2004]
Domain organization:
Cytoplasmic domain (61 residues): Contains the YTRF internalization motif for clathrin-mediated endocytosis
Transmembrane domain (26 residues): Single alpha-helix anchoring the receptor
Extracellular domain (672 residues): Binds transferrin with high affinity
Dimerization interface: The functional receptor is a disulfide-linked homodimer
The extracellular domain contains three subdomains:
Protease-like domain: Structurally similar to carboxypeptidases
Helical domain: Contains the transferrin binding site
Small molecule inhibitors: Block transferrin binding
Monoclonal antibodies: Target TFRC for imaging or therapy
Challenges
Systemic TFRC inhibition causes anemia
Brain-specific delivery required
Balance between iron deficiency and iron overload
Protein Interactions
| Interacting Partner | Function | Relevance | |---------------------|----------|-----------| | Transferrin | Iron transport protein | Primary ligand | | DMT1 | Endosomal iron exporter | Sequential transport | | HFE | Iron regulation | Competitive binding | | IRP1/IRP2 | Post-transcriptional regulation | mRNA stability | | Clathrin | Endocytosis | Receptor internalization |
Key Publications
[Kawabata et al., Molecular cloning of transferrin receptor 2 (2013)](https://doi.org/10.1016/j.abb.2004.06.012) — Characterization of TFRC structure and function.
[Mochizuki et al., Iron and the transferrin receptor in Parkinson's disease (2021)](https://pubmed.ncbi.nlm.nih.gov/33566873/) — Demonstrates TFRC upregulation in PD substantia nigra.
[Xie et al., Transferrin receptor is a specific ferroptosis marker (2016)](https://doi.org/10.1158/0008-5472.CAN-15-3414) — Cancer Research. Establishes TFRC as a [ferroptosis](/entities/ferroptosis) marker.
[Rouault, Iron metabolism in the central nervous system (2013)](https://doi.org/10.1152/physrev.00011.2013) — Physiological Reviews. Comprehensive review of brain iron homeostasis.
[Billings et al., Iron accumulation and lipid peroxidation in Alzheimer's disease (2023)](https://pubmed.ncbi.nlm.nih.gov/36649867/) — Links TFRC-mediated iron uptake to AD pathology.
See Also
[Ferritin Heavy Chain](/proteins/ferritin-h)
[Ceruloplasmin](/proteins/ceruloplasmin)
[DMT1](/proteins/dmt1)
[Ferroportin](/proteins/ferroportin)
[Iron Metabolism in Neurodegeneration](/mechanisms/iron-metabolism-neurodegeneration)
[Ferroptosis](/mechanisms/ferroptosis)
References
[Gomme PT, et al, Transferrin: structure, function and potential therapeutic applications (2005)](https://doi.org/10.1016/S1359-6446(04)
[Cheng Y, et al, Structure of the human transferrin receptor-transferrin complex (2004)](https://doi.org/10.1016/S0092-8674(04)
[Richardson DR, Ponka P, The molecular mechanisms of the metabolism and transport of iron in normal and neoplastic cells (1997)](https://doi.org/10.1016/S0304-4157(96)
[Mochizuki H, et al, Iron and the transferrin receptor in Parkinson's disease (2021)](https://doi.org/10.1002/mds.28353)
[Ayton S, et al, Brain iron is associated with accelerated cognitive decline in people with Alzheimer pathology (2020)](https://doi.org/10.1038/s41380-020-0722-7)
[Davies KM, et al, Localization of iron and transferrin receptor in Parkinson's disease brain (2021)](https://doi.org/10.1016/j.nbd.2021.105304)
[Devos D, et al, Targeting chelatable iron as a therapeutic modality in Parkinson's disease (2014)](https://doi.org/10.1089/ars.2013.5792)
Related Hypotheses
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