GO:0030350 iron-responsive element binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0030350 iron-responsive element binding is a molecular function defined as binding to an iron-responsive element (IRE), a regulatory sequence in the 5'- or 3'-untranslated regions of mRNAs encoding many iron-binding proteins.
• The primary proteins that execute this function are iron regulatory proteins IRP1 (ACO1) and IRP2 (IREB2), which bind IREs to control mRNA translation or stability.
• IRE binding is regulated by cellular iron status: IRP1 switches between a cytosolic aconitase and an RNA-binding form via an iron-sulfur cluster, while IRP2 is degraded by the proteasome under high iron.
• IRE binding controls key iron homeostasis genes including FTH1, FTL, TFRC, DMT1, and ferroportin, thereby regulating iron uptake, storage, and export.
• Dysregulated IRE binding is linked to ferroptosis, ferritinophagy, neurodegeneration, and cancer, making it a target for therapeutic intervention.
• Experimental approaches to study IRE binding include biotinylated IRE pull-down assays, electrophoretic mobility shift assays (EMSA), and CRISPR-based knockout or point-mutation models.
Description
Iron-responsive element (IRE) binding is a molecular function that governs post-transcriptional control of iron metabolism. The Gene Ontology term GO:0030350, iron-responsive element binding, is defined as binding to an iron-responsive element, a regulatory sequence found in the 5'- and 3'-untranslated regions of mRNAs encoding many iron-binding proteins. This function is essential for maintaining cellular iron homeostasis and preventing iron-induced oxidative stress. IRE binding is performed by iron regulatory proteins (IRPs), which sense iron levels and modulate the translation or stability of target mRNAs. The importance of IRE binding extends beyond basic iron metabolism; it impacts diverse physiological processes such as erythropoiesis, immune function, and neuronal survival. Dysregulation of IRE binding has been implicated in diseases including cancer, neurodegeneration, and organ injury. Researchers study IRE binding to understand how cells adapt to iron fluctuations and to develop therapies for iron-related disorders. This article provides a comprehensive overview of the mechanism, key genes, regulatory pathways, disease associations, and experimental methods for investigating GO:0030350.
iron-responsive element binding At A Glance
| GO ID | GO:0030350 |
|---|---|
| GO term | iron-responsive element binding |
| Ontology | molecular_function |
| Synonym | IRE binding |
| Definition | Binding to an iron-responsive element, a regulatory sequence found in the 5'- and 3'-untranslated regions of mRNAs encoding many iron-binding proteins. |
| Major function | Post-transcriptional regulation of iron metabolism genes |
| Primary proteins | IRP1 (ACO1), IRP2 (IREB2) |
| Regulatory mechanism | Iron-sulfur cluster switch (IRP1) and proteasomal degradation (IRP2) |
| Target mRNAs | FTH1, FTL, TFRC, DMT1, ferroportin, etc. |
What Is GO:0030350?
GO:0030350 iron-responsive element binding is a molecular function that describes the selective interaction of a protein with an iron-responsive element (IRE). An IRE is a conserved RNA stem-loop structure located in the 5'- or 3'-untranslated regions (UTRs) of mRNAs that encode proteins involved in iron uptake, storage, and export. The binding of proteins to IREs regulates mRNA translation or stability, thereby controlling iron homeostasis. This function is primarily mediated by iron regulatory proteins IRP1 and IRP2, which bind IREs under low-iron conditions to either inhibit translation (when the IRE is in the 5'-UTR) or stabilize the mRNA (when the IRE is in the 3'-UTR).
Why Is iron-responsive element binding Important in Cell Biology?
Iron-responsive element binding is critical for maintaining cellular iron homeostasis, as it allows cells to rapidly adjust the expression of proteins involved in iron uptake, storage, and export in response to changing iron levels. This function prevents both iron deficiency and iron overload, which can lead to oxidative stress and cell death. Dysregulation of IRE binding is associated with a wide range of human diseases, including neurodegenerative disorders, cancer, and organ injury. Understanding IRE binding mechanisms provides insights into fundamental RNA-protein interactions and offers potential therapeutic targets for iron-related pathologies.
• Maintains cellular iron homeostasis by regulating translation and stability of iron metabolism mRNAs.
• Prevents iron-induced oxidative stress and ferroptosis.
• Controls systemic iron absorption and distribution through regulation of DMT1 and ferroportin.
• Plays a role in erythropoiesis by regulating ferritin and transferrin receptor expression.
• Implicated in neurodegenerative diseases such as Alzheimer's and Parkinson's.
• Dysregulated in cancer, where altered iron metabolism supports tumor growth.
• Target for therapeutic intervention in iron overload disorders and ferroptosis-related diseases.
• Provides a model for studying RNA-protein interactions and post-transcriptional gene regulation.
• Essential for immune cell function and host defense against pathogens.
• Involved in organ injury and repair processes through ferritinophagy.
Molecular Mechanism of iron-responsive element binding
Iron-Sulfur Cluster Switch in IRP1
In simple terms: IRP1 can switch between two forms: one that binds RNA and one that acts as an enzyme, depending on whether it has an iron-sulfur cluster.
IRP1 (also known as ACO1) is a bifunctional protein that contains a [4Fe-4S] cluster. When iron is abundant, the cluster is assembled, and IRP1 functions as a cytosolic aconitase, converting citrate to isocitrate. Under low-iron conditions, the cluster disassembles, causing a conformational change that exposes the RNA-binding site, allowing IRP1 to bind IREs with high affinity. This switch is a key regulatory mechanism for iron homeostasis.
IRP2 Regulation by Proteasomal Degradation
In simple terms: IRP2 is always an RNA-binding protein, but it gets destroyed when iron levels are high.
IRP2 (IREB2) lacks an iron-sulfur cluster and is primarily regulated by iron-dependent degradation. In iron-replete cells, IRP2 is oxidized and targeted for ubiquitination and proteasomal degradation, reducing its ability to bind IREs. Under low iron, IRP2 is stabilized and binds IREs to modulate target mRNA translation or stability.
IRE Recognition and Binding Specificity
In simple terms: IRPs recognize a specific RNA hairpin structure called an IRE, and the exact shape and sequence matter for binding.
IREs are conserved stem-loop structures with a specific loop sequence (CAGUGN) and a bulge. IRP1 and IRP2 bind to these elements with high specificity. The binding affinity can vary depending on the IRE sequence and context, allowing differential regulation of target mRNAs. Structural studies have revealed that IRP1 undergoes a large conformational change to accommodate the IRE stem-loop.
Post-Transcriptional Outcomes of IRE Binding
In simple terms: When an IRP binds to an IRE, it can either block translation or protect the mRNA from degradation, depending on where the IRE is located.
If the IRE is in the 5'-UTR, IRP binding typically inhibits translation initiation, reducing protein synthesis (e.g., ferritin H and L chains). If the IRE is in the 3'-UTR, IRP binding stabilizes the mRNA, increasing protein production (e.g., transferrin receptor 1, DMT1). This dual mechanism allows coordinated regulation of iron uptake and storage.
Non-Canonical IREs and Additional Factors
In simple terms: Some IREs have unusual structures and can bind other proteins, expanding the regulatory network.
Non-canonical IREs, such as the one in the 3'-UTR of Trichomonas vaginalis TvCP12 mRNA, can bind proteins like TvHSP70 and TvACTN-3, affecting mRNA stability and protein levels. These findings suggest that IRE binding is not limited to IRPs and may involve diverse RNA-binding proteins in different organisms.
Key Genes Involved in GO:0030350 iron-responsive element binding
The following genes encode proteins that either bind IREs directly or are regulated by IRE binding, playing key roles in iron metabolism and related cellular processes.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACO1 (IRP1) | Binds IREs; cytosolic aconitase | Central regulator of iron homeostasis; iron-sulfur cluster switch |
| IREB2 (IRP2) | Binds IREs; regulated by iron-dependent degradation | Key mediator of iron sensing; implicated in neurodegeneration |
| FTH1 | Ferritin heavy chain; iron storage | 5'-UTR IRE; translation inhibited by IRP binding |
| FTL | Ferritin light chain; iron storage | 5'-UTR IRE; translation inhibited by IRP binding |
| TFRC | Transferrin receptor 1; iron uptake | 3'-UTR IREs; mRNA stabilized by IRP binding |
| SLC11A2 (DMT1) | Divalent metal transporter 1; iron uptake | 3'-UTR IRE; regulated by IRP binding; affects Notch signaling |
| SLC40A1 | Ferroportin; iron export | 5'-UTR IRE; translation inhibited by IRP binding |
| NCOA4 | Ferritinophagy receptor | Regulates ferritin degradation; linked to ferroptosis |
| HSPA8 (HSP70) | Chaperone; binds non-canonical IREs | Modulates mRNA stability in Trichomonas vaginalis |
| ACTN3 | Actinin; binds non-canonical IREs | Regulates mRNA stability in Trichomonas vaginalis |
| TvCP12 | Cysteine protease; contains IRE in 3'-UTR | Model for non-canonical IRE function |
| APP | Amyloid precursor protein; iron metabolism | 5'-UTR IRE; linked to Alzheimer's disease |
| SNCA | Alpha-synuclein; iron metabolism | IRE-mediated regulation; linked to Parkinson's disease |
| HIF1A | Hypoxia-inducible factor 1-alpha | Indirectly linked to iron metabolism and IRE binding |
| NFE2L2 | Nrf2; oxidative stress response | Cross-talk with iron metabolism and ferroptosis |
| GPX4 | Glutathione peroxidase 4; ferroptosis regulator | Iron-dependent lipid peroxidation; linked to IRE binding |
| SLC7A11 | Cystine/glutamate transporter | Ferroptosis defense; influenced by iron metabolism |
| BECN1 | Beclin-1; autophagy regulator | Autophagy-ferritinophagy crosstalk |
How Is iron-responsive element binding Regulated?
IRE binding activity is primarily regulated by cellular iron levels. In iron-replete conditions, IRP1 assembles a [4Fe-4S] cluster and loses RNA-binding activity, while IRP2 is degraded by the proteasome. Conversely, iron deficiency stabilizes the RNA-binding forms of both IRPs. Additional regulation occurs through oxidative stress, which can modulate IRP1 cluster stability and IRP2 degradation. Furthermore, autophagy and ferritinophagy can influence iron availability and indirectly affect IRE binding activity. Non-canonical IRE-binding proteins may be regulated by distinct mechanisms, such as interaction with chaperones.
iron-responsive element binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| IREB2 (IRP2) | Neurodegeneration, cancer | KO and point-mutation cell lines; neuronal cultures |
| ACO1 (IRP1) | Iron overload, oxidative stress | Knock-in of mutant IRP1; hepatocyte models |
| FTH1 | Ferroptosis, organ injury | Overexpression and KO; ferroptosis induction |
| TFRC | Cancer, anemia | Knockout and overexpression; tumor xenografts |
| SLC11A2 (DMT1) | Iron deficiency, Notch signaling | KO and point-mutation; intestinal epithelial cells |
Neurodegeneration
Dysregulated IRE binding is implicated in neurodegenerative diseases such as Alzheimer's and Parkinson's, where iron accumulation and oxidative stress contribute to neuronal death. IRP2 is overexpressed in affected brain regions, leading to altered expression of ferritin and transferrin receptor. Mutations in IREs or IRPs can disrupt iron homeostasis and promote neurodegeneration.
Cancer
Cancer cells often reprogram iron metabolism to support rapid proliferation. Altered IRE binding activity can increase iron uptake and storage, promoting tumor growth. For example, IRP2 is upregulated in some cancers, leading to increased TFRC expression and iron acquisition. Targeting IRE binding pathways is being explored as a therapeutic strategy.
Ferroptosis and Organ Injury
Ferroptosis is an iron-dependent form of cell death characterized by lipid peroxidation. IRE binding regulates key ferroptosis modulators, including ferritin and GPX4. Autophagy-induced ferritinophagy releases free iron, sensitizing cells to ferroptosis. This process is implicated in organ injury, including kidney and liver damage.
Infectious Disease
Non-canonical IREs in pathogens such as Trichomonas vaginalis can bind host or parasite proteins to regulate mRNA stability, influencing virulence. The IRE-tvcp12 hairpin in T. vaginalis binds TvHSP70 and TvACTN-3, affecting cysteine protease expression and potentially pathogenesis.
From iron-responsive element binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of IRP1 affect iron homeostasis? | ACO1 knockout cell line (e.g., HepG2, HEK293) |
| How does IRP2 mutation affect neurodegeneration? | IREB2 point-mutation knock-in mice or neuronal cells |
| What is the effect of ferritin IRE mutation on translation? | FTH1 5'-UTR IRE knock-in reporter cell line |
| Can overexpression of IRP2 induce ferroptosis? | Doxycycline-inducible IRP2 overexpression in cancer cells |
| How does DMT1 IRE regulate Notch signaling? | SLC11A2 3'-UTR IRE knockout or mutation in intestinal cells |
| Does NCOA4-mediated ferritinophagy require IRE binding? | NCOA4 knockout and IRP1/2 double knockout cells |
How to Study the iron-responsive element binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Biotinylated IRE pull-down | IRE-binding protein levels and activity | Comparing IRP activity in iron-replete vs. iron-deficient cells |
| EMSA | RNA-protein complex formation | Detecting IRE-binding activity in cell extracts |
| RIP-seq / CLIP-seq | Transcriptome-wide IRE binding sites | Mapping IRP target mRNAs in different tissues |
| CRISPR knockout screens | Genes affecting IRE regulation | Identifying modifiers of iron homeostasis |
| Western blot | Protein expression of IRP1, IRP2, ferritin, TFRC | Validating changes in iron metabolism proteins |
| Luciferase reporter assays | IRE-mediated translational control | Testing IRE mutations or IRP mutants |
| Proteomics | Global protein expression changes | Assessing downstream effects of IRE binding |
| Imaging (iron staining) | Cellular iron distribution | Visualizing iron accumulation in knockout models |
Biotinylated IRE Pull-Down Assays
Biotinylated IRE probes can be used to pull down IRP1 and IRP2 from cell lysates, followed by Western blotting or mass spectrometry. This method allows assessment of IRE-binding activity under different iron conditions and is quantitative when combined with streptavidin detection.
Electrophoretic Mobility Shift Assay (EMSA)
EMSA uses radiolabeled or fluorescent IRE probes incubated with cell extracts. The formation of RNA-protein complexes is detected by gel electrophoresis. This classic technique measures IRE-binding activity and can be supershifted with antibodies to identify specific proteins.
RNA Immunoprecipitation (RIP) and CLIP
RIP and CLIP (cross-linking and immunoprecipitation) enable identification of endogenous mRNAs bound by IRPs in living cells. Coupled with next-generation sequencing (RIP-seq, CLIP-seq), these methods provide transcriptome-wide maps of IRE binding sites and reveal regulatory networks.
CRISPR-Based Genetic Screens
Genome-wide CRISPR knockout or activation screens can identify genes that modulate IRE binding activity or iron homeostasis. For example, a reporter cell line with an IRE-driven fluorescent protein can be used to sort cells with altered IRE regulation, followed by sequencing to identify sgRNAs.
How CRISPR Can Be Used to Study GO:0030350 iron-responsive element binding
Knockout
CRISPR knockout of ACO1 (IRP1) or IREB2 (IRP2) in cell lines such as HepG2 or HEK293 can reveal their specific roles in iron homeostasis. Double knockout of both IRPs is often lethal or causes severe iron dysregulation, highlighting their essential functions. Knockout models are used to study ferroptosis sensitivity and ferritinophagy.
Point Mutation
Point mutations in the iron-sulfur cluster ligands of IRP1 (e.g., Cys437Ser) can lock the protein in either the RNA-binding or aconitase form, allowing dissection of the switch mechanism. Similarly, mutations in the IRE stem-loop of target mRNAs (e.g., FTH1 IRE) can abolish IRP binding and deregulate translation.
Knock-in
Knock-in of tagged IRP1 or IRP2 (e.g., FLAG or HA) enables endogenous protein detection and immunoprecipitation for RIP-seq studies. Knock-in of mutant IREs in the endogenous locus of target genes (e.g., TFRC 3'-UTR) allows physiological analysis of IRE-mediated regulation.
Overexpression
Overexpression of wild-type or mutant IRP1/IRP2 in cell lines can mimic iron-deficient or iron-overloaded states. Inducible overexpression systems are useful to study acute effects on iron metabolism and ferroptosis. Overexpression of non-canonical IRE-binding proteins (e.g., TvHSP70) can be used to study their role in mRNA stability.
How EDITGENE Supports iron-responsive element binding Research
Researchers studying iron-responsive element binding-related genes often need to determine whether a candidate gene is causally involved in iron homeostasis, ferroptosis, or disease progression. EDITGENE provides comprehensive CRISPR-based services to create precise cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for iron-responsive element binding research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ACO1 Knockout HEK293 Cell Line | EDJ-KQ3552 | Human | 48 | Details Get a Quote |
| IREB2 Knockout HEK293 Cell Line | EDJ-KQ5005 | Human | 3658 | Details Get a Quote |
| ACO1 Knockout A-549 Cell Line | EDJ-KQ25408 | Human | 48 | Details Get a Quote |
| ACO1 Knockout HCT 116 Cell Line | EDJ-KQ25409 | Human | 48 | Details Get a Quote |
| ACO1 Knockout HeLa Cell Line | EDJ-KQ25410 | Human | 48 | Details Get a Quote |
| IREB2 Knockout A-549 Cell Line | EDJ-KQ27908 | Human | 3658 | Details Get a Quote |
| IREB2 Knockout HCT 116 Cell Line | EDJ-KQ27909 | Human | 3658 | Details Get a Quote |
| IREB2 Knockout HeLa Cell Line | EDJ-KQ27910 | Human | 3658 | Details Get a Quote |
Displaying Records 1 To 8 Of 8 Records
Frequently Asked Questions About iron-responsive element binding
What is iron-responsive element binding?
Iron-responsive element binding is a molecular function (GO:0030350) where a protein binds to a specific RNA stem-loop called an IRE, typically found in the UTRs of mRNAs encoding iron metabolism proteins, to regulate their translation or stability.
What genes are involved in iron-responsive element binding?
The main genes are ACO1 (IRP1) and IREB2 (IRP2), which encode the iron regulatory proteins. Other genes regulated by IRE binding include FTH1, FTL, TFRC, SLC11A2 (DMT1), and SLC40A1.
How does iron regulate IRE binding activity?
Iron regulates IRP1 via an iron-sulfur cluster switch: high iron promotes cluster assembly and aconitase activity, while low iron exposes the RNA-binding site. IRP2 is degraded by the proteasome under high iron, reducing IRE binding.
What diseases are associated with defective IRE binding?
Defective IRE binding is linked to neurodegeneration, cancer, ferroptosis-related organ injury, and infectious diseases. For example, IRP2 dysregulation is observed in Alzheimer's and Parkinson's diseases.
How can I study IRE binding in the lab?
Common methods include biotinylated IRE pull-down assays, EMSA, RIP-seq, and CRISPR-based knockout or reporter screens. These techniques measure IRE-binding activity and identify target mRNAs.
What is the role of IRE binding in ferroptosis?
IRE binding regulates ferritin and transferrin receptor expression, affecting labile iron pools. Autophagy-induced ferritinophagy releases iron, and altered IRE binding can sensitize cells to ferroptosis.
Can CRISPR be used to study IRE binding?
Yes, CRISPR knockout of ACO1 or IREB2, point mutations in IRP1, or knock-in of tagged IRPs are powerful approaches to dissect IRE binding mechanisms and their physiological consequences.
What are non-canonical IREs?
Non-canonical IREs are RNA structures that deviate from the classic stem-loop but still bind proteins. An example is the IRE in the 3'-UTR of Trichomonas vaginalis TvCP12 mRNA, which binds TvHSP70 and TvACTN-3.
How does IRE binding affect iron storage?
When IRPs bind to 5'-UTR IREs of ferritin mRNAs (FTH1, FTL), they inhibit translation, reducing iron storage. This prevents excess iron accumulation under low-iron conditions.
What cell models are available for IRE binding research?
EDITGENE provides knockout, point-mutation, knock-in, and overexpression cell models for key IRE-binding genes, as well as CRISPR library screening and bioinformatics services to support iron metabolism research.
Conclusion
Iron-responsive element binding (GO:0030350) is a fundamental molecular function that controls iron homeostasis at the post-transcriptional level. Through the action of IRP1 and IRP2, cells dynamically regulate the expression of proteins involved in iron uptake, storage, and export. Dysregulation of this process contributes to a variety of human diseases, including neurodegeneration, cancer, and ferroptosis-related organ injury. Continued research using advanced CRISPR models and RNA-protein interaction techniques will further elucidate the complexities of IRE binding and open new therapeutic avenues.
References
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- 3. Zhang DL et al.. 2024. Using Biotinylated Iron-Responsive Element to Analyze the Activity of Iron Regulatory Proteins.. Int J Mol Sci 25(9) PMID: 38732071
- 4. Rouault TA et al.. 1992. An iron-sulfur cluster plays a novel regulatory role in the iron-responsive element binding protein.. Biometals 5(3):131-40 PMID: 1421965
- 5. Luo C et al.. 2025. Autophagy induced by mechanical stress sensitizes cells to ferroptosis by NCOA4-FTH1 axis.. Autophagy 21(6):1263-1282 PMID: 39988734
- 6. Shao N et al.. 2026. Ferritinophagy and organ injury.. Autophagy 22(6):1171-1185 PMID: 41692973
- 7. Hounjet J et al.. 2023. Iron-responsive element of Divalent metal transporter 1 (Dmt1) controls Notch-mediated cell fates.. FEBS J 290(24):5811-5834 PMID: 37646174
- 8. León-Sicairos CR et al.. 2023. The Non-Canonical Iron-Responsive Element of IRE-tvcp12 Hairpin Structure at the 3'-UTR of Trichomonas vaginalis TvCP12 mRNA That Binds TvHSP70 and TvACTN-3 Can Regulate mRNA Stability and Amount of Protein.. Pathogens 12(4) PMID: 37111472
