GO:0002113 interleukin-33 binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0002113 (interleukin-33 binding) is a molecular function defined as binding to interleukin-33 (IL-33), a nuclear alarmin and IL-1 family cytokine.
• IL-33 binding is mediated by its receptor ST2 (IL1RL1) and by non-receptor partners such as RAGE and ZBP1, enabling both ST2-dependent and ST2-independent signaling.
• IL-33 is released during cell stress, allergen exposure, and necroptosis, where its binding to ZBP1 contributes to macrophage necroptosis and airway inflammation.
• The IL-33/ST2 axis is implicated in type 2 immunity, allergic airway disease, COPD, gout, and tumor biology, making it a therapeutic target.
• Structural and computational studies have identified putative IL-33 binding sites within the IL-1 family fold, guiding mutagenesis and drug design.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect IL-33 binding partners and downstream signaling in disease contexts.
Description
Interleukin-33 (IL-33) is a dual-function cytokine of the IL-1 family that acts as a nuclear alarmin and as an extracellular ligand for the ST2 receptor. The molecular function GO:0002113, interleukin-33 binding, describes the selective interaction of proteins with IL-33, a step that initiates both canonical ST2-dependent signaling and non-canonical pathways. This binding event is central to type 2 immune responses, tissue repair, and inflammatory pathology, and it has become a focal point for therapeutic intervention in asthma, COPD, and other diseases. Researchers study interleukin-33 binding to understand how IL-33 is sensed by immune and structural cells, how its release is regulated, and how aberrant binding contributes to chronic inflammation. The interaction of IL-33 with ST2 triggers NF-kB and MAPK signaling, while binding to RAGE or ZBP1 can drive ST2-independent effects such as epithelial pathogenesis or necroptosis. These diverse binding partners underscore the need for precise molecular tools to map interaction interfaces and functional consequences. This article synthesizes authoritative QuickGO annotation and verified PubMed literature to provide a research-grade overview of GO:0002113, covering its definition, mechanism, key genes, disease relevance, and experimental strategies including CRISPR-based models.
interleukin-33 binding At A Glance
| GO ID | GO:0002113 |
|---|---|
| GO term | interleukin-33 binding |
| Ontology | molecular_function |
| Synonym | IL-33 binding |
| Definition | Binding to interleukin-33. |
| Major function | Mediates recognition of IL-33 by receptors and intracellular sensors, initiating signaling or regulatory events. |
| Key binding partners | ST2 (IL1RL1), RAGE, ZBP1, and other IL-1 family-related proteins. |
| Disease relevance | Allergic airway inflammation, COPD, gout, and type 2 immunity. |
| Research methods | Surface plasmon resonance, co-immunoprecipitation, CRISPR knockouts, and molecular dynamics simulations. |
What Is GO:0002113?
GO:0002113 (interleukin-33 binding) is a molecular function term defined by the Gene Ontology as the binding to interleukin-33. It encompasses any protein-protein interaction where one molecule selectively binds IL-33, whether as a receptor (e.g., ST2/IL1RL1), a decoy receptor, a signaling adaptor, or a structural partner. This function is distinct from IL-33 production or secretion and focuses on the recognition event itself.
Why Is interleukin-33 binding Important in Cell Biology?
Interleukin-33 binding is a critical checkpoint in innate and adaptive immunity because it determines whether IL-33 acts as a danger signal, a homeostatic cytokine, or a driver of chronic inflammation. The binding of IL-33 to ST2 activates type 2 immune cells, but alternative binding to RAGE or ZBP1 can promote ST2-independent pathology such as epithelial remodeling in COPD or macrophage necroptosis in asthma models. Understanding these interactions at the molecular level is essential for designing biologics or small molecules that selectively block pathogenic IL-33 binding without compromising protective immunity.
• IL-33 binding to ST2 is a hallmark of type 2 immune activation in asthma and allergy.
• ST2-independent IL-33 binding to RAGE drives epithelial pathogenesis in COPD.
• IL-33 binding to ZBP1 mediates macrophage necroptosis in HDM-induced airway inflammation.
• The IL-33/ST2 axis is genetically and epigenetically regulated in gout and innate immune responses.
• IL-33 binding is linked to gasdermin D and gasdermin C activation in allergic airway diseases.
• Structural insights into IL-33 binding sites inform drug discovery for IL-1 family cytokines.
• CRISPR screens can identify novel IL-33 binding partners and modifiers of its release.
• IL-33 binding is a therapeutic target in COPD, asthma, and other chronic inflammatory diseases.
Molecular Mechanism of interleukin-33 binding
IL-33 recognition by ST2 (IL1RL1)
In simple terms: IL-33 binds to its primary receptor ST2 on the surface of immune cells, like a key fitting a lock.
The canonical interleukin-33 binding event occurs when extracellular IL-33 engages the ST2 receptor (IL1RL1), a member of the IL-1 receptor family. This interaction recruits the co-receptor IL-1RAcP and activates NF-kB and MAPK signaling, leading to type 2 cytokine production. The binding affinity and kinetics of IL-33 to ST2 have been characterized in multiple studies, and this axis is central to allergic inflammation.
ST2-independent binding to RAGE
In simple terms: Sometimes IL-33 binds to a different receptor called RAGE, especially when IL-33 is oxidized, triggering inflammation without ST2.
Oxidized IL-33 can bind to RAGE and form a signaling complex with EGFR, driving epithelial pathogenesis in COPD independently of ST2. This alternative binding mode expands the functional repertoire of interleukin-33 binding and highlights the importance of post-translational modifications in dictating partner selection.
Intracellular binding to ZBP1 and necroptosis
In simple terms: Inside cells, IL-33 can bind to ZBP1, a sensor that triggers a form of cell death called necroptosis.
PTRF-mediated IL-33 release leads to its binding to ZBP1, which activates necroptosis in macrophages and contributes to HDM-induced airway inflammation. This intracellular interleukin-33 binding event represents a non-canonical function that links alarmin release to programmed cell death.
Structural basis of IL-33 binding
In simple terms: The 3D shape of IL-33 determines which proteins it can bind, and computer simulations help identify these binding sites.
Mixed-solvent molecular dynamics simulations of the IL-1 family have revealed putative binding sites on IL-33, providing a structural framework for understanding its interactions with receptors and other partners. These computational approaches complement experimental mutagenesis and binding assays to map the interleukin-33 binding interface.
Regulation by proteases and gasdermins
In simple terms: Enzymes called proteases and proteins called gasdermins control how IL-33 is released and whether it can bind to its partners.
Allergen protease-activated stress granule assembly and gasdermin D fragmentation regulate IL-33 secretion, thereby controlling the availability of IL-33 for binding. Iron drives protease-independent cleavage of gasdermin D in allergic airway diseases, further influencing IL-33 release and subsequent binding events. Gasdermin C-mediated type 2 immunity in intraepithelial mast cells also modulates IL-33 bioavailability.
Key Genes Involved in GO:0002113 interleukin-33 binding
The following genes encode proteins that bind IL-33 or regulate its availability and downstream signaling, making them key players in GO:0002113 research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| IL1RL1 (ST2) | Primary receptor for IL-33; mediates canonical signaling | Target for asthma and allergy therapeutics; KO models available |
| IL33 | Ligand; nuclear alarmin and cytokine | Source of IL-33 for binding studies; overexpression and KO models |
| AGER (RAGE) | ST2-independent receptor for oxidized IL-33 | Implicated in COPD epithelial pathogenesis |
| ZBP1 | Intracellular sensor that binds IL-33 and triggers necroptosis | Mediates HDM-induced airway inflammation |
| PTRF (CAVIN1) | Regulates IL-33 release and ZBP1-mediated necroptosis | Link between caveolae and IL-33 secretion |
| GSDMD | Gasdermin D; controls IL-33 secretion via fragmentation | Allergen protease-activated stress granule assembly |
| GSDMC | Gasdermin C; mediates type 2 immunity in mast cells | Intraepithelial mast cell-driven IL-33 release |
| IL1RAP | Co-receptor for ST2 signaling | Required for IL-33/ST2 signal transduction |
| MYD88 | Adaptor downstream of ST2 | Canonical IL-33 signaling pathway |
| NFKB1 | Transcription factor activated by IL-33 binding | Drives inflammatory gene expression |
| MAPK1 | Kinase activated by IL-33/ST2 | Type 2 cytokine production |
| EGFR | Partners with RAGE in oxidized IL-33 signaling | COPD pathogenesis |
| RIPK3 | Kinase involved in necroptosis downstream of ZBP1 | Macrophage necroptosis in airway inflammation |
| MLKL | Executioner of necroptosis | ZBP1-mediated cell death |
| CASP1 | Inflammasome caspase; may regulate IL-33 processing | Innate immune response to gout |
| NLRP3 | Inflammasome sensor linked to IL-33 release | Gout and innate immunity |
| IL1B | IL-1 family cytokine; shares signaling components | Comparative studies with IL-33 |
| IL1RN | IL-1 receptor antagonist; modulates IL-1 family signaling | Regulation of IL-33 binding context |
How Is interleukin-33 binding Regulated?
Interleukin-33 binding is regulated at multiple levels. The availability of IL-33 is controlled by proteolytic cleavage and gasdermin-mediated secretion, as shown by allergen protease-activated stress granule assembly and gasdermin D fragmentation. Iron-dependent, protease-independent gasdermin D cleavage further modulates IL-33 release in allergic airway diseases. Post-translational oxidation of IL-33 switches its binding preference from ST2 to RAGE, altering downstream signaling. Additionally, the expression of the ST2 receptor is regulated by genetic and epigenetic mechanisms in innate immune cells, influencing the capacity for IL-33 binding. These layers of regulation ensure that interleukin-33 binding is context-dependent and tightly controlled.
interleukin-33 binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| IL1RL1 (ST2) | Asthma, allergic inflammation | ST2 knockout mouse; human airway epithelial cells |
| AGER (RAGE) | COPD | RAGE knockout mouse; oxidized IL-33 treatment |
| ZBP1 | HDM-induced airway inflammation | ZBP1 knockout macrophages; necroptosis assays |
| GSDMD | Allergic airway disease | GSDMD knockout mouse; allergen protease challenge |
| GSDMC | Type 2 immunity | Mast cell-specific GSDMC knockout |
IL-33 binding in allergic airway inflammation and asthma
IL-33 binding to ST2 on type 2 innate lymphoid cells and mast cells drives allergic airway inflammation. Allergen proteases activate stress granule assembly and gasdermin D fragmentation, promoting IL-33 secretion and subsequent binding. In HDM-induced airway inflammation, IL-33 binding to ZBP1 mediates macrophage necroptosis, exacerbating tissue damage. These pathways are being targeted for asthma therapeutics.
IL-33 binding in COPD
Oxidized IL-33 binds to RAGE and EGFR, forming a ST2-independent signaling complex that drives epithelial pathogenesis in COPD. This alternative binding mode highlights the importance of IL-33 oxidation state in disease and suggests that blocking RAGE or EGFR may be beneficial in COPD patients with high oxidative stress.
IL-33 binding in gout and innate immunity
Genetic and epigenetic regulation of the innate immune response to gout involves IL-1 family cytokines, including IL-33. IL-33 binding to its receptor may amplify inflammasome-dependent inflammation in gout, although the exact mechanisms are still under investigation.
IL-33 binding in type 2 immunity and mast cell biology
Intraepithelial mast cells drive gasdermin C-mediated type 2 immunity, which is linked to IL-33 release and binding. This pathway is critical for host defense against helminths but can also contribute to allergic pathology.
From interleukin-33 binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ST2 mediate IL-33 binding in type 2 immunity? | IL1RL1 knockout mouse or human cell line |
| Does oxidized IL-33 bind RAGE in COPD? | AGER knockout epithelial cells treated with oxidized IL-33 |
| Is ZBP1 required for IL-33-induced necroptosis? | ZBP1 knockout macrophages |
| Does gasdermin D cleavage regulate IL-33 secretion? | GSDMD knockout mouse or airway epithelial cells |
| What is the binding affinity of IL-33 to ST2 mutants? | Point-mutation knock-in of IL1RL1 in cell lines |
| Can overexpression of IL-33 drive inflammation? | IL-33 overexpression transgenic mouse |
How to Study the interleukin-33 binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Surface plasmon resonance | Binding affinity and kinetics | IL-33/ST2 interaction studies |
| Co-immunoprecipitation | Protein-protein interactions | Identifying IL-33 binding partners in cell lysates |
| CRISPR knockout screen | Genes required for IL-33 binding or signaling | Discovery of novel regulators |
| Molecular dynamics simulation | Putative binding sites and conformational changes | Structure-based drug design |
| ELISA | IL-33 concentration in supernatants | Measuring IL-33 release |
| Flow cytometry | Cell surface ST2 expression | Identifying IL-33-responsive cells |
| Western blot | Protein expression and cleavage | Gasdermin D fragmentation |
| Necroptosis assay | Cell death pathway activation | ZBP1-mediated necroptosis |
Surface plasmon resonance (SPR) for binding kinetics
SPR measures real-time binding affinity and kinetics between IL-33 and its partners, such as ST2 or RAGE. This label-free method is ideal for comparing wild-type and mutant IL-33 or receptor variants to map the interleukin-33 binding interface.
Co-immunoprecipitation and pull-down assays
Co-immunoprecipitation of IL-33 with candidate binding proteins from cell lysates confirms physical interactions in native contexts. Pull-down assays using recombinant IL-33 can identify novel binding partners from tissue extracts.
CRISPR knockout screens for IL-33 binding regulators
Genome-wide CRISPR knockout screens can identify genes required for IL-33 binding, secretion, or downstream signaling. Such screens have revealed roles for gasdermins and stress granule components in IL-33 biology.
Molecular dynamics simulations
Mixed-solvent molecular dynamics simulations of the IL-1 family have been used to predict putative binding sites on IL-33, guiding mutagenesis and drug design. These computational methods complement experimental structural biology.
How CRISPR Can Be Used to Study GO:0002113 interleukin-33 binding
Knockout
CRISPR knockout of IL1RL1 (ST2), AGER, or ZBP1 eliminates specific interleukin-33 binding events, allowing researchers to attribute downstream phenotypes to a particular receptor or sensor. For example, ST2 knockout mice are widely used to study type 2 immunity, while ZBP1 knockout macrophages are used to dissect necroptosis.
Point Mutation
Point mutations in the IL-33 binding interface of ST2 or RAGE can abrogate binding without affecting surface expression, providing precise tools to test the functional consequences of interleukin-33 binding. Such mutants are valuable for validating computational predictions of binding sites.
Knock-in
Knock-in of tagged IL-33 or ST2 (e.g., HA or GFP) enables live-cell imaging and proximity labeling to map interleukin-33 binding dynamics in real time. Knock-in of disease-associated variants can model human genetic susceptibility.
Overexpression
Overexpression of IL-33 or its binding partners in cell lines or transgenic mice amplifies signaling and can reveal gain-of-function phenotypes, such as spontaneous inflammation or enhanced type 2 immunity. Overexpression models are also useful for producing recombinant proteins for binding assays.
How EDITGENE Supports interleukin-33 binding Research
Researchers studying interleukin-33 binding-related genes often need to determine whether a candidate gene is causally involved in IL-33 recognition, release, or downstream signaling. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell and animal models, enabling rigorous functional validation of interleukin-33 binding mechanisms.
Contact EDITGENE today to design your custom CRISPR model for interleukin-33 binding research.
Frequently Asked Questions About interleukin-33 binding
What is interleukin-33 binding?
Interleukin-33 binding (GO:0002113) is a molecular function defined as the binding to interleukin-33, a cytokine of the IL-1 family. It includes interactions with receptors like ST2 and non-canonical partners such as RAGE and ZBP1.
What genes are involved in interleukin-33 binding?
Key genes include IL1RL1 (ST2), AGER (RAGE), ZBP1, PTRF, GSDMD, GSDMC, and IL1RAP, among others.
What is the role of ST2 in IL-33 binding?
ST2 (IL1RL1) is the primary receptor for IL-33 and mediates canonical signaling that drives type 2 immune responses.
How is IL-33 released for binding?
IL-33 is released during cell stress, allergen exposure, and necroptosis, often through gasdermin D or C pores and stress granule assembly.
What diseases are linked to interleukin-33 binding?
IL-33 binding is implicated in asthma, COPD, gout, and other inflammatory diseases.
Can CRISPR be used to study interleukin-33 binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect IL-33 binding mechanisms and disease relevance.
What is the difference between ST2-dependent and ST2-independent IL-33 binding?
ST2-dependent binding activates canonical NF-kB signaling, while ST2-independent binding to RAGE or ZBP1 can drive epithelial pathogenesis or necroptosis.
How can I measure IL-33 binding affinity?
Surface plasmon resonance and co-immunoprecipitation are commonly used to measure binding affinity and identify interaction partners.
Is IL-33 binding involved in cancer?
The IL-33/ST2 axis has been implicated in tumor biology, though its role is context-dependent and requires further study.
What model systems are available for IL-33 binding research?
Knockout mice, transgenic overexpression models, and human cell lines with CRISPR edits are widely used.
Conclusion
Interleukin-33 binding (GO:0002113) is a pivotal molecular function that governs the initiation of type 2 immunity, tissue repair, and inflammatory pathology. The interaction of IL-33 with ST2, RAGE, ZBP1, and other partners determines whether IL-33 acts as a protective alarmin or a driver of chronic disease. Understanding these binding events at structural and functional levels is essential for developing targeted therapies for asthma, COPD, and related disorders. CRISPR-based models, combined with biochemical and computational methods, provide a robust toolkit to dissect interleukin-33 binding mechanisms and translate these insights into clinical applications. EDITGENE offers end-to-end services to support these research efforts.
References
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- 2. Chen W et al.. 2022. Allergen protease-activated stress granule assembly and gasdermin D fragmentation control interleukin-33 secretion.. Nat Immunol 23(7):1021-1030 PMID: 35794369
- 3. Sheng F et al.. 2025. IL-33/ST2 axis in diverse diseases: regulatory mechanisms and therapeutic potential.. Front Immunol 16:1533335 PMID: 39925809
- 4. Du J et al.. 2023. PTRF-IL33-ZBP1 signaling mediating macrophage necroptosis contributes to HDM-induced airway inflammation.. Cell Death Dis 14(7):432 PMID: 37454215
- 5. Chen S et al.. 2026. Iron drives protease-independent cleavage of gasdermin D in allergic airway diseases.. Cell 189(16):5012-5025.e10 PMID: 42361797
- 6. Yang L et al.. 2024. Intraepithelial mast cells drive gasdermin C-mediated type 2 immunity.. Immunity 57(5):1056-1070.e5 PMID: 38614091
- 7. de Lima JD et al.. 2023. Genetic and Epigenetic Regulation of the Innate Immune Response to Gout.. Immunol Invest 52(3):364-397 PMID: 36745138
- 8. Mai TT et al.. 2024. Toward Unveiling Putative Binding Sites of Interleukin-33: Insights from Mixed-Solvent Molecular Dynamics Simulations of the Interleukin-1 Family.. J Phys Chem B 128(35):8362-8375 PMID: 39178050
