GO:0050543 icosatetraenoic acid binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0050543 (icosatetraenoic acid binding) is a molecular function describing the selective, non-covalent interaction of a protein with any straight-chain C20 fatty acid carrying four double bonds, including arachidonic acid and its oxygenated derivatives.
• The term is experimentally anchored by ligand-binding assays such as radioimmunoassay and radioligand receptor-binding studies performed on leukotriene B4 and its omega-oxidized metabolite.
• Icosatetraenoic acid binding underlies inflammatory lipid mediator recognition, as shown for 5-oxo-icosatetraenoic acids that trigger neutrophil chemotaxis, calcium transients, actin reorganization and superoxide production.
• Enzymes of the 5-lipoxygenase pathway generate the icosatetraenoic acid-derived ligands that are subsequently bound by receptors and carrier proteins.
• The function is relevant to immune regulation, since a 14,15-dihydroxy-icosatetraenoic acid inhibits human natural killer cell activity.
• Bioinformatic and machine-learning analyses of autophagy-related genes in heart failure illustrate how lipid-binding gene sets can be mined for disease signatures.
Description
GO:0050543, icosatetraenoic acid binding, is a Gene Ontology molecular function that captures the ability of a protein to bind icosatetraenoic acid, defined as any straight-chain fatty acid with twenty carbon atoms and four double bonds per molecule. This class of ligand includes arachidonic acid and a broad family of oxygenated eicosanoid derivatives, such as leukotriene B4 and 5-oxo-icosatetraenoic acids, which act as potent local mediators. The term is therefore central to understanding how cells sense and respond to lipid signals during inflammation and immune surveillance. Experimentally, icosatetraenoic acid binding has been documented through direct ligand-detection methods. A radioimmunoassay for leukotriene B4 provided one of the earliest quantitative tools for measuring this icosatetraenoic acid derivative in biological samples, and a receptor for the 20-hydroxy derivative of leukotriene B4 was demonstrated on human neutrophils by radioligand binding. These studies established that specific, saturable protein-ligand interactions with icosatetraenoic acids are measurable and biologically meaningful. For researchers, GO:0050543 provides a controlled vocabulary for annotating proteins that recognize this lipid class, enabling functional enrichment, target prioritization and mechanistic dissection of eicosanoid signaling. Because icosatetraenoic acid derivatives drive neutrophil responses and modulate natural killer cell activity, the term bridges molecular binding events to cellular immunology and to disease processes in which lipid mediators are dysregulated.
icosatetraenoic acid binding At A Glance
| GO ID | GO:0050543 |
|---|---|
| GO term | icosatetraenoic acid binding |
| Ontology | molecular_function |
| Synonym | eicosatetraenoic acid binding |
| Definition | Binding to icosatetraenoic acid, any straight-chain fatty acid with twenty carbon atoms and four double bonds per molecule. |
| Ligand class | Straight-chain C20 fatty acids with four double bonds, including arachidonic acid and oxygenated eicosanoids |
| Representative ligands | Leukotriene B4, 20-hydroxy leukotriene B4, 5-oxo-icosatetraenoic acids, 14,15-dihydroxy-icosatetraenoic acid |
| Experimental evidence | Radioligand binding, radioimmunoassay and functional neutrophil response assays |
What Is GO:0050543?
In plain terms, GO:0050543 describes the function of a protein that physically binds icosatetraenoic acid, a twenty-carbon fatty acid containing four double bonds. The binding is non-covalent and selective for this structural class of lipid, which includes arachidonic acid and its oxidized metabolites. The term is a molecular function, meaning it describes what a protein does at the molecular level rather than where it acts or which pathway it belongs to.
Why Is icosatetraenoic acid binding Important in Cell Biology?
Icosatetraenoic acid binding is important because it is the molecular recognition step that allows cells to detect and respond to a large family of lipid mediators. These mediators include leukotriene B4, whose measurement by radioimmunoassay helped define eicosanoid biology, and 5-oxo-icosatetraenoic acids, which activate a distinctive pattern of neutrophil responses including calcium transients, actin reorganization and superoxide production. The same ligand class can also suppress immune function, as shown by inhibition of human natural killer cell activity by a 14,15-dihydroxy-icosatetraenoic acid. Consequently, proteins annotated with GO:0050543 are candidate nodes for understanding inflammation, immune regulation and lipid-driven disease mechanisms.
• Defines the molecular recognition step for arachidonic acid and its oxygenated metabolites, a major class of inflammatory lipid mediators.
• Provides a functional annotation for receptors and carrier proteins that bind leukotriene B4 and related icosatetraenoic acids.
• Links directly to neutrophil activation, including chemotaxis, calcium signaling, actin reorganization and superoxide anion production.
• Extends to immune suppression, since a 14,15-dihydroxy-icosatetraenoic acid inhibits human natural killer cell activity.
• Connects to the 5-lipoxygenase biosynthetic pathway that generates icosatetraenoic acid-derived ligands.
• Supports biomarker and bioinformatics studies of lipid-related gene sets in complex diseases such as heart failure.
• Relevant to essential fatty acid and endocannabinoid biology, where C20 polyunsaturated fatty acids serve as precursors and signals.
• Enables target discovery for anti-inflammatory and immunomodulatory research through enrichment of GO:0050543-annotated proteins.
Molecular Mechanism of icosatetraenoic acid binding
Ligand recognition and binding specificity
In simple terms: A protein must first recognize and grab the icosatetraenoic acid molecule.
Icosatetraenoic acid binding begins with selective recognition of a straight-chain C20 fatty acid bearing four double bonds. The structural definition encompasses arachidonic acid and its oxygenated derivatives, and experimental work has demonstrated direct binding of leukotriene B4 by radioimmunoassay and of the 20-hydroxy derivative of leukotriene B4 by radioligand receptor-binding assays on human neutrophils. These studies show that binding is saturable and specific, providing the molecular basis for the GO:0050543 annotation.
Receptor engagement and signal initiation
In simple terms: Once bound, the protein-lipid complex can switch on a cellular response.
Binding of icosatetraenoic acids to their protein partners initiates downstream signaling. Chemotactic 5-oxo-icosatetraenoic acids activate a unique pattern of neutrophil responses, including phospholipid metabolism, intracellular Ca2+ transients, actin reorganization, superoxide-anion production and receptor up-regulation. The demonstration of a receptor for the 20-hydroxy derivative of leukotriene B4 on human neutrophils further supports the concept that specific icosatetraenoic acid-binding proteins transduce lipid signals into cellular activation.
Biosynthetic origin of the ligands
In simple terms: The lipids that are bound are produced by dedicated enzymes.
The icosatetraenoic acid ligands recognized by GO:0050543-annotated proteins are generated through enzymatic oxidation. Native and mutant 5-lipoxygenase expression studies in a baculovirus/insect cell system established a tractable model for producing and analyzing this enzyme, which converts arachidonic acid into leukotriene intermediates. Radioimmunoassays for leukotrienes of slow reacting substance of anaphylaxis provided complementary tools for quantifying these products. Together, these methods define the ligand supply that feeds icosatetraenoic acid-binding events.
Modulation of immune cell function
In simple terms: Binding of these lipids can either activate or suppress immune cells.
The functional consequences of icosatetraenoic acid binding are cell-type dependent. In neutrophils, 5-oxo-icosatetraenoic acids drive a pro-inflammatory program, whereas a 14,15-dihydroxy-icosatetraenoic acid inhibits human natural killer cell activity. This dichotomy illustrates that GO:0050543 describes a binding function whose physiological output depends on the specific ligand, the protein partner and the cellular context. The leukotriene B4 radioimmunoassay developed by Lewis and colleagues provided an early quantitative framework for studying such ligand-receptor interactions.
Integration with lipid mediator networks
In simple terms: These binding events are part of a larger network of fatty acid signals.
Icosatetraenoic acid binding sits within a broader network of essential fatty acid and endocannabinoid signaling, in which C20 polyunsaturated fatty acids serve as precursors and mediators. The oxidation of leukotrienes at the omega end, demonstrated by the identification of a receptor for the 20-hydroxy derivative of leukotriene B4, shows that metabolic transformation of the icosatetraenoic acid backbone can create new ligands with distinct binding properties. This network view helps researchers interpret GO:0050543 annotations in the context of whole-pathway biology.
Key Genes Involved in GO:0050543 icosatetraenoic acid binding
The following genes and proteins are experimentally or functionally linked to icosatetraenoic acid binding and its associated lipid mediator pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ALOX5 | 5-lipoxygenase, converts arachidonic acid to leukotriene intermediates | Native and mutant enzyme expression established a model for studying icosatetraenoic acid-derived ligand production |
| LTB4R | Receptor for leukotriene B4, a prototypical icosatetraenoic acid derivative | Leukotriene B4 radioimmunoassay and receptor studies underpin ligand-binding quantification |
| LTB4R2 | Second leukotriene B4 receptor mediating chemotaxis | Relevant to neutrophil responses triggered by icosatetraenoic acid derivatives |
| CYP4F3 | Omega-oxidation of leukotriene B4 to 20-hydroxy leukotriene B4 | The 20-hydroxy derivative binds a demonstrated neutrophil receptor |
| PTGS1 | Cyclooxygenase-1, oxidizes arachidonic acid to prostaglandin intermediates | Contributes to the pool of icosatetraenoic acid-derived mediators |
| PTGS2 | Cyclooxygenase-2, inducible arachidonic acid oxidation | Links icosatetraenoic acid metabolism to inflammatory gene expression |
| ALOX15 | 12/15-lipoxygenase, produces 14,15-dihydroxy-icosatetraenoic acid | Its product inhibits human natural killer cell activity |
| ALOX5AP | 5-lipoxygenase activating protein, supports leukotriene synthesis | Required for efficient generation of icosatetraenoic acid-derived ligands |
| PLA2G4A | Cytosolic phospholipase A2, releases arachidonic acid from membranes | Supplies the substrate for icosatetraenoic acid-binding pathways |
| FAAH | Fatty acid amide hydrolase, degrades endocannabinoid-related fatty acid amides | Connects C20 fatty acid signaling to endocannabinoid biology |
| CNR1 | Cannabinoid receptor 1, binds endocannabinoid ligands | Illustrates lipid-binding protein families related to icosatetraenoic acid signaling |
| CNR2 | Cannabinoid receptor 2, binds endocannabinoid ligands | Relevant to immune modulation by fatty acid mediators |
| MAP1LC3B | Autophagy-related protein used in bioinformatic gene signatures | Identified in autophagy-related gene analyses of heart failure |
| BECN1 | Autophagy regulator included in disease gene panels | Example of how lipid-related gene sets are mined in complex disease |
| ATG5 | Core autophagy gene used in machine-learning feature selection | Demonstrates bioinformatic prioritization of gene sets |
| ATG12 | Autophagy conjugation factor in disease gene signatures | Supports integrative analysis of lipid and autophagy pathways |
| NLRP3 | Inflammasome sensor responsive to lipid mediators | Connects icosatetraenoic acid signaling to innate immunity |
| NFKB1 | Transcription factor downstream of inflammatory lipid signaling | Mediates gene expression changes following icosatetraenoic acid binding |
How Is icosatetraenoic acid binding Regulated?
Icosatetraenoic acid binding is regulated at the level of ligand availability and receptor expression. The supply of icosatetraenoic acid derivatives depends on the activity of biosynthetic enzymes such as 5-lipoxygenase, whose native and mutant forms have been characterized in a baculovirus/insect cell expression system. Receptor up-regulation is part of the cellular response to chemotactic 5-oxo-icosatetraenoic acids, as shown in neutrophils. In addition, omega-oxidation of leukotrienes generates the 20-hydroxy derivative that engages a distinct neutrophil receptor, illustrating metabolic control of binding specificity. Quantitative tools such as radioimmunoassays for leukotriene B4 and related slow-reacting substances of anaphylaxis allow researchers to monitor ligand levels that influence these binding events.
icosatetraenoic acid binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ALOX5 | Leukotriene-mediated inflammation | Knockout or point-mutation cell lines to abolish icosatetraenoic acid-derived ligand production |
| LTB4R | Neutrophil chemotaxis and inflammatory recruitment | Receptor knockout and tagged knock-in for ligand-binding assays |
| ALOX15 | Natural killer cell suppression by 14,15-dihydroxy-icosatetraenoic acid | Overexpression and knockout models to test immune modulation |
| CYP4F3 | Omega-oxidation of leukotriene B4 and receptor engagement | Knock-in of catalytic mutants to dissect 20-hydroxy derivative binding |
| MAP1LC3B | Autophagy-related gene signature in heart failure | CRISPR knockout in cardiomyocyte-like cells for functional validation |
Inflammatory and immune disorders
Icosatetraenoic acid binding is mechanistically tied to inflammation through leukotriene B4 and 5-oxo-icosatetraenoic acids, which activate neutrophil chemotaxis, calcium signaling, actin reorganization and superoxide production. The presence of a specific receptor for the 20-hydroxy derivative of leukotriene B4 on human neutrophils further links this binding function to inflammatory cell recruitment. Dysregulation of these lipid-protein interactions is therefore a plausible contributor to chronic inflammatory pathology.
Immune suppression and natural killer cell biology
Not all icosatetraenoic acid-binding events are pro-inflammatory. A 14,15-dihydroxy-icosatetraenoic acid inhibits human natural killer cell activity, demonstrating that specific oxygenated derivatives can suppress immune effector function. This finding positions GO:0050543-annotated proteins as potential modulators of anti-tumor and anti-viral immunity, and suggests that the balance of different icosatetraenoic acid ligands shapes immune outcomes.
Cardiometabolic and autophagy-related disease
Bioinformatic and machine-learning analyses have identified autophagy-related genes in heart failure, illustrating how lipid- and autophagy-linked gene sets can be prioritized in cardiometabolic disease research. Although these analyses are computational, they provide hypotheses about how icosatetraenoic acid-binding proteins and related pathways may intersect with cardiac stress responses. Essential fatty acid and endocannabinoid biology provides additional context for the role of C20 polyunsaturated fatty acids in metabolic regulation.
From icosatetraenoic acid binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene abolish icosatetraenoic acid binding? | CRISPR knockout cell line followed by radioligand binding assay |
| Does a specific amino acid residue mediate ligand recognition? | Point-mutation knock-in of the predicted binding residue |
| Can a tagged protein be used to pull down icosatetraenoic acid ligands? | Tagged knock-in of the endogenous locus |
| Does overexpression of a biosynthetic enzyme increase ligand availability? | Overexpression cell model for 5-lipoxygenase or related enzymes |
| Which genes are required for neutrophil responses to 5-oxo-icosatetraenoic acids? | CRISPR library screening in neutrophil-like cells |
| Can bioinformatic signatures be validated functionally? | Knockout of autophagy-related candidates identified in heart failure analyses |
How to Study the icosatetraenoic acid binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding assay | Direct, saturable binding of labeled icosatetraenoic acid derivatives | Receptor characterization on neutrophils and transfected cells |
| Radioimmunoassay | Concentration of leukotriene B4 and related eicosanoids | Quantification of ligands in biological samples |
| Neutrophil functional assay | Calcium transients, actin reorganization, superoxide production | Testing 5-oxo-icosatetraenoic acid responses |
| Natural killer cell cytotoxicity assay | Immune effector function | Testing suppression by 14,15-dihydroxy-icosatetraenoic acid |
| Baculovirus/insect cell expression | Enzymatic activity of 5-lipoxygenase variants | Producing and characterizing ligand-generating enzymes |
| Bioinformatic machine learning | Gene signature discovery from expression datasets | Identifying autophagy-related genes in heart failure |
| Lipid mediator profiling | Panel of fatty acid-derived mediators | Contextualizing icosatetraenoic acid binding within networks |
Radioligand binding assays
Direct measurement of icosatetraenoic acid binding relies on radiolabeled ligands. The demonstration of a receptor for the 20-hydroxy derivative of leukotriene B4 on human neutrophils used radioligand binding to establish saturable, specific interaction. Similar approaches can be applied to candidate proteins annotated with GO:0050543 to determine affinity and specificity.
Radioimmunoassay for lipid mediators
Radioimmunoassay provides a sensitive method for quantifying icosatetraenoic acid derivatives. A radioimmunoassay for leukotriene B4 was developed to measure this lipid in biological samples, and radioimmunoassays for the leukotrienes of slow reacting substance of anaphylaxis extended this capability to related eicosanoids. These assays are useful for correlating ligand levels with binding activity.
Functional cell-based assays
Because icosatetraenoic acid binding leads to measurable cellular responses, functional assays complement direct binding measurements. Chemotactic 5-oxo-icosatetraenoic acids activate phospholipid metabolism, intracellular Ca2+ transients, actin reorganization, superoxide-anion production and receptor up-regulation in neutrophils, providing a multi-parameter readout of binding-dependent signaling. Natural killer cell cytotoxicity assays can detect the suppressive effect of 14,15-dihydroxy-icosatetraenoic acid.
Enzyme expression and bioinformatic analysis
Production of icosatetraenoic acid ligands can be studied by expressing biosynthetic enzymes such as native and mutant 5-lipoxygenase in baculovirus/insect cell systems. On the data-analysis side, bioinformatic and machine-learning approaches have been used to identify autophagy-related genes in heart failure, illustrating how gene sets can be prioritized for follow-up binding studies. Essential fatty acid and endocannabinoid reviews provide conceptual frameworks for interpreting these results.
How CRISPR Can Be Used to Study GO:0050543 icosatetraenoic acid binding
Knockout
CRISPR knockout of candidate genes such as ALOX5, LTB4R or ALOX15 can test whether loss of the protein abolishes icosatetraenoic acid binding or downstream cellular responses. For example, removing a receptor for the 20-hydroxy derivative of leukotriene B4 would be expected to eliminate the specific binding signal detected on human neutrophils. Knockout models also allow functional assays such as neutrophil chemotaxis and superoxide production to be linked to the binding event.
Point Mutation
Point-mutation knock-in can dissect the structural determinants of ligand recognition. By mutating predicted binding residues in a receptor or carrier protein, researchers can determine whether a single amino acid is required for icosatetraenoic acid binding. This approach parallels the characterization of native and mutant 5-lipoxygenase, where enzyme variants were expressed to study function. Point mutants are also useful for separating binding from downstream signaling.
Knock-in
Knock-in of epitope or fluorescent tags at the endogenous locus enables direct visualization and pull-down of icosatetraenoic acid-binding proteins. Tagged receptors can be used in radioligand binding assays or affinity purification to confirm interaction with leukotriene B4 or 5-oxo-icosatetraenoic acids. Knock-in of reporter cassettes can also monitor receptor up-regulation following ligand exposure.
Overexpression
Overexpression of biosynthetic enzymes or binding proteins can amplify icosatetraenoic acid signaling for biochemical analysis. Expression of native and mutant 5-lipoxygenase in a baculovirus/insect cell system provided a scalable source of enzyme for studying ligand production. Overexpression of a candidate binding protein can similarly increase signal in radioimmunoassay or functional assays.
How EDITGENE Supports icosatetraenoic acid binding Research
Researchers studying icosatetraenoic acid binding-related genes often need to determine whether a candidate gene is causally involved in ligand recognition, downstream signaling or disease-associated phenotypes. Establishing causality requires precise genetic models that can remove, modify or tag the gene of interest without confounding off-target effects. EDITGENE provides the full spectrum of CRISPR-engineered cell models needed to move from correlation to mechanism in GO:0050543 research.
Contact EDITGENE today to design your custom CRISPR model for icosatetraenoic acid binding research.
Frequently Asked Questions About icosatetraenoic acid binding
What is icosatetraenoic acid binding?
Icosatetraenoic acid binding is the molecular function defined by GO:0050543, describing the non-covalent binding of a protein to any straight-chain C20 fatty acid with four double bonds, including arachidonic acid and its oxygenated derivatives.
What genes are involved in icosatetraenoic acid binding?
Genes experimentally linked to this function and its pathways include ALOX5, LTB4R, LTB4R2, CYP4F3, ALOX15, ALOX5AP and PLA2G4A, based on studies of leukotriene B4, 5-oxo-icosatetraenoic acids and related mediators.
What is the GO ID for icosatetraenoic acid binding?
The Gene Ontology identifier is GO:0050543, with the synonym eicosatetraenoic acid binding.
Which ligands bind to proteins annotated with GO:0050543?
Representative ligands include leukotriene B4, its 20-hydroxy derivative, 5-oxo-icosatetraenoic acids and 14,15-dihydroxy-icosatetraenoic acid.
How is icosatetraenoic acid binding measured experimentally?
Common methods include radioligand binding assays, radioimmunoassay for leukotriene B4 and related eicosanoids, and functional neutrophil or natural killer cell assays.
Why is icosatetraenoic acid binding important in inflammation?
It mediates neutrophil chemotaxis, calcium signaling, actin reorganization and superoxide production in response to 5-oxo-icosatetraenoic acids, and supports receptor engagement by leukotriene B4 derivatives.
Can icosatetraenoic acid binding suppress immune responses?
Yes, a 14,15-dihydroxy-icosatetraenoic acid inhibits human natural killer cell activity, showing that some icosatetraenoic acid-binding events are immunosuppressive.
Which enzyme produces icosatetraenoic acid-derived ligands?
5-lipoxygenase, encoded by ALOX5, converts arachidonic acid into leukotriene intermediates, and its native and mutant forms have been characterized in baculovirus/insect cell systems.
How can CRISPR help study icosatetraenoic acid binding?
CRISPR knockout, point mutation, knock-in and overexpression models allow researchers to test whether specific genes and residues are required for ligand binding and downstream cellular responses.
Is icosatetraenoic acid binding linked to heart failure?
Bioinformatic and machine-learning analyses have identified autophagy-related genes in heart failure, providing a framework for prioritizing lipid- and autophagy-linked gene sets for functional study.
Conclusion
GO:0050543, icosatetraenoic acid binding, defines a molecular function that connects C20 polyunsaturated fatty acids and their oxygenated derivatives to specific protein partners. Experimental evidence from radioligand binding, radioimmunoassay and functional cell assays demonstrates that these interactions are saturable, specific and biologically consequential, driving neutrophil activation and modulating natural killer cell activity. The function is embedded in a broader network of essential fatty acid and endocannabinoid signaling. For researchers, GO:0050543 offers a precise annotation to guide target discovery and mechanistic studies in inflammation and immune regulation. Combining CRISPR-engineered cell models with ligand-binding and functional assays provides a rigorous path from gene to mechanism, and EDITGENE supports every step of that workflow.
References
- 1. Lewis RA et al.. 1982. Radioimmunoassay for leukotriene B4.. Proc Natl Acad Sci U S A 79(24):7904-8 PMID: 6296855
- 2. Ramstedt U et al.. 1984. Inhibition of human natural killer cell activity by (14R,15S)-14,15-dihydroxy-5Z,8Z,10E,12E- icosatetraenoic acid.. Proc Natl Acad Sci U S A 81(22):6914-8 PMID: 6095260
- 3. Clancy RM et al.. 1984. Oxidation of leukotrienes at the omega end: demonstration of a receptor for the 20-hydroxy derivative of leukotriene B4 on human neutrophils and implications for the analysis of leukotriene receptors.. Proc Natl Acad Sci U S A 81(18):5729-33 PMID: 6091105
- 4. Norgauer J et al.. 1996. Chemotactic 5-oxo-icosatetraenoic acids activate a unique pattern of neutrophil responses. Analysis of phospholipid metabolism, intracellular Ca2+ transients, actin reorganization, superoxide-anion production and receptor up-regulation.. Eur J Biochem 236(3):1003-9 PMID: 8665888
- 5. Deng X et al.. 2024. Identification of 4 autophagy-related genes in heart failure by bioinformatics analysis and machine learning.. Front Cardiovasc Med 11:1247079 PMID: 38347953
- 6. Caramia G. 2012. [Essential fatty acids and lipid mediators. Endocannabinoids].. Pediatr Med Chir 34(2):65-72 PMID: 22730630
- 7. Funk CD et al.. 1989. Native and mutant 5-lipoxygenase expression in a baculovirus/insect cell system.. Proc Natl Acad Sci U S A 86(8):2592-6 PMID: 2649885
- 8. Levine L et al.. 1981. Radioimmunoassay of the leukotrienes of slow reacting substance of anaphylaxis.. Proc Natl Acad Sci U S A 78(12):7692-6 PMID: 6950409
