Transferrin receptor 1

Transferrin receptor protein 1 (TfR1), also known as Cluster of Differentiation 71 (CD71), is a protein that in humans is encoded by the TFRC gene.^[5][6] TfR1 is required for iron import from transferrin into cells by endocytosis.^[7][8]

TFRC
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1CX8, 1DE4, 1SUV, 2NSU, 3KAS, 3S9L, 3S9M, 3S9N
Identifiers
Aliases	TFRC, CD71, T9, TFR, TFR1, TR, TRFR, p90, IMD46, transferrin receptor
External IDs	OMIM: 190010; MGI: 98822; HomoloGene: 2429; GeneCards: TFRC; OMA:TFRC - orthologs
Gene location (Human) Chr. Chromosome 3 (human)[1] Band 3q29 Start 196,027,183 bp[1] End 196,082,096 bp[1]
Gene location (Mouse) Chr. Chromosome 16 (mouse)[2] Band 16 B3|16 23.06 cM Start 32,427,738 bp[2] End 32,451,612 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in endothelial cell trabecular bone tibia germinal epithelium visceral pleura hair follicle parietal pleura periodontal fiber mucosa of sigmoid colon bone marrow Top expressed in fetal liver hematopoietic progenitor cell body of femur habenula stroma of bone marrow tibiofemoral joint temporal muscle human fetus vastus lateralis muscle digastric muscle ankle More reference expression data BioGPS More reference expression data
Gene ontology Molecular function protein homodimerization activity virus receptor activity transferrin receptor activity identical protein binding double-stranded RNA binding RNA binding protein binding Cellular component extracellular vesicle integral component of membrane recycling endosome HFE-transferrin receptor complex endosome blood microparticle membrane melanosome plasma membrane integral component of plasma membrane extracellular region cell surface basolateral plasma membrane perinuclear region of cytoplasm clathrin-coated pit extracellular exosome external side of plasma membrane extracellular space clathrin-coated vesicle membrane cytoplasmic vesicle endosome membrane early endosome Biological process endocytosis osteoclast differentiation positive regulation of bone resorption receptor-mediated endocytosis regulation of cell population proliferation regulation of cell growth viral entry into host cell viral process cellular iron ion homeostasis positive regulation of isotype switching receptor internalization transferrin transport positive regulation of B cell proliferation positive regulation of T cell proliferation membrane organization cellular response to leukemia inhibitory factor iron ion transport Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 7037 22042 Ensembl ENSG00000072274 ENSMUSG00000022797 UniProt P02786 Q62351 RefSeq (mRNA) NM_001313965 NM_001313966 NM_001128148 NM_003234 NM_011638 NM_001357298 RefSeq (protein) NP_001121620 NP_001300894 NP_001300895 NP_003225 NP_035768 NP_001344227 Location (UCSC) Chr 3: 196.03 – 196.08 Mb Chr 16: 32.43 – 32.45 Mb PubMed search [3] [4]
Wikidata
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Structure and function

TfR1 = transferrin receptor 1 in Human iron metabolism.

TfR1 is a transmembrane glycoprotein composed of two disulfide-linked monomers joined by two disulfide bonds. Each monomer binds one holo-transferrin molecule creating an iron-Tf-TfR complex which enters the cell by endocytosis.^[9]

Clinical significance

TfR1 as a potential new target in cases of human leukemia & lymphoma. InatherYs, in Évry, France, developed a candidate drug, INA01 antibody (anti-CD71) that showed efficacy in pre-clinical studies in the therapy of two incurable orphan oncohematological diseases: the adult T cell leukemia (ATLL) caused by HTLV-1 and the Mantle cell lymphoma (MCL).^{[citation needed]}

TfR1 expressed on the endothelial cells of the blood-brain barrier (BBB) is used also in preclinical research to allow the delivery of large molecules including antibodies into the brain.^[10] Some of the TfR1 targeting antibodies have been shown to cross the blood-brain barrier, without interfering with the uptake of iron. Amongst those are the mouse anti rat-TfR antibody OX26^[11] and the rat anti mouse-TfR antibody 8D3.^[12] The affinity of the antibody-TfR interaction seems to be important determining the success of transcytotic transport over endothelial cells of the BBB. Monovalent TfR interaction favors BBB transport due to altered intracellular sorting pathways. Avidity effects of bivalent interactions redirecting transport to the lysosome.^[13] Also, reducing TfR binding affinity directly promote dissociation from the TfR which increase brain parenchymal exposure of the TfR binding antibody.^[14]

Interactions

TfR1 has been shown to interact with GABARAP^[15] and HFE.^[16][17]

Immunostain marker

CD71 is a robust immunohistochemistry marker for chorionic villi, especially in necrotic specimens. Among white blood cells and precursors, CD71 is expressed only by erythroid precursors within the normal hematopoietic marrow and spleen, in contrast to glycophorin that marks all types of red blood cells.^[18]

See also

• Transferrin receptor 2
• Cluster of differentiation