| Topic | Key recent finding | Evidence type/model | Practical implication | Primary citations (pqac IDs) |
|---|---|---|---|---|
| TFRC/TfR1 core function and trafficking | Human TFRC encodes TfR1/CD71, a homodimeric type II transmembrane receptor that binds diferric transferrin, internalizes via clathrin/AP-2-mediated endocytosis, releases iron in acidic endosomes, and recycles apo-transferrin/TfR1 to the surface; the cytoplasmic YTRF motif is critical for internalization. | Mechanistic reviews and human disease-focused primary study; receptor biology and trafficking synthesis. | Establishes the primary molecular function for functional annotation: transferrin-dependent cellular iron import coupled to rapid endocytic recycling, with the YTRF motif explaining trafficking-sensitive pathogenic variants and engineering opportunities. | (pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000004) |
| 2024 immune deficiency findings | A new homozygous TFRC p.R22W variant, alongside known p.Y20H, disrupts the YTRF-region internalization machinery, increases surface TfR1, impairs receptor shuttling/iron uptake, and causes combined immunodeficiency with defective T/B-cell activation, restricted clonal diversity, hypogammaglobulinemia, cytopenias, recurrent infections, and reduced NK/Treg/MAIT cells; some proliferative defects were partially rescued by exogenous iron. | 2024 human genetics and immunology study in patient cells, engineered HEK293T constructs, flow cytometry, Seahorse metabolic assays, transcriptomics. | Shows TfR1 is not only an iron receptor but a nonredundant immune-metabolic checkpoint; supports TFRC inclusion in inborn error of immunity workups and motivates iron-uptake rescue or HSCT-based management strategies. | (pqac-00000015, pqac-00000016, pqac-00000018, pqac-00000021) |
| 2024 ferroptosis-related regulatory axes | Multiple 2024 studies place TFRC as a positive ferroptosis node: reduced FTO increases m6A-dependent stability of Tfrc/Acsl4 transcripts in aged liver I/R injury; CCT3-ACTN4 limits TFRC recycling to the plasma membrane and thereby suppresses iron endocytosis/ferroptosis in sorafenib-resistant HCC; HIF1A transcriptionally upregulates TFRC in breast cancer, increasing Fe2+ and lipid peroxidation and restoring Adriamycin sensitivity. | 2024 primary mechanistic studies using mouse liver I/R models, primary hepatocytes, HCC cell lines/xenografts, breast cancer clinical samples/cell models, dual-luciferase assays, ferroptosis rescue assays. | Identifies TFRC trafficking/expression as a therapeutically actionable lever for ferroptosis modulation in cancer and ischemia-reperfusion injury, including overcoming drug resistance. | (pqac-00000024, pqac-00000025, pqac-00000026, pqac-00000029) |
| Applications: BBB targeting, cancer delivery, sTfR biomarker | TfR1 remains a major receptor-mediated transcytosis target at the BBB; successful design principles emphasize monovalent/moderate-affinity binding, pH-dependent dissociation, recycling-biased epitopes, and controlled ligand density to avoid lysosomal trapping. Cancer implementations include transferrin- or anti-TfR1-based nanoparticles, liposomes, micelles, toxin conjugates, and protein-derived carbon dots. Soluble TfR (sTfR) serves as a clinical marker of tissue iron demand/erythropoiesis; in a 2023 HF cohort, a pragmatic cutoff of >1.63 mg/L identified patients with worse 6MWT and quality-of-life outcomes. | 2024 delivery reviews, 2024 nanoparticle/cell-targeting study, 2023 prospective human heart-failure cohort with regression analyses and figure/table support. | Guides translational use of TFRC in brain drug delivery and tumor targeting, while highlighting biomarker utility of sTfR and the lack of universally standardized cutoffs. | (pqac-00000031, pqac-00000033, pqac-00000035, pqac-00000038, pqac-00000011, pqac-00000012, pqac-00000039) |


*Table: This table condenses the most important TFRC/TfR1 findings for functional annotation, recent mechanistic advances, and translational relevance. It is useful as a quick-reference summary linking core biology to 2024 immune and ferroptosis studies and current application areas.*