GO:0047676 arachidonate-CoA ligase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0047676 arachidonate-CoA ligase activity catalyzes the ATP-dependent ligation of arachidonate with coenzyme A to form arachidonoyl-CoA, AMP, diphosphate, and H+.
• The enzyme was first discovered in human platelets and is distinct from nonspecific long-chain acyl-CoA synthetases.
• Arachidonoyl-CoA synthetase activity is widely distributed across tissues, including brain microvessels and microvascular endothelium.
• Triacsin C differentially inhibits arachidonoyl-CoA synthetase relative to nonspecific long-chain acyl-CoA synthetase, providing a pharmacological tool.
• Fatty acid structural requirements are stringent, with arachidonic acid (20:4) being a preferred substrate.
• Mutations in FACL4 (ACSL4), a related fatty acid-CoA ligase, cause nonspecific X-linked mental retardation, linking this activity to neurodevelopment.
Description
Arachidonate-CoA ligase activity (GO:0047676) is a molecular function that catalyzes the ATP-dependent formation of arachidonoyl-CoA from arachidonate and coenzyme A. This reaction is the first committed step in the metabolic activation of arachidonic acid, a polyunsaturated fatty acid that serves as the precursor for eicosanoids such as prostaglandins, thromboxanes, and leukotrienes. The enzyme was initially discovered in human platelets, where it plays a critical role in thromboxane A2 production and platelet aggregation. Since its discovery, arachidonoyl-CoA synthetase activity has been detected in various tissues, including brain microvessels, microvascular endothelium, and other cell types, indicating a broad physiological relevance. Researchers study this activity to understand lipid signaling, inflammatory responses, and the metabolic reprogramming observed in cancer and neurological disorders. The enzyme's distinct substrate specificity and differential inhibition by triacsin C make it a unique target for investigating arachidonic acid metabolism.
arachidonate-CoA ligase activity At A Glance
| GO ID | GO:0047676 |
|---|---|
| GO term | arachidonate-CoA ligase activity |
| Ontology | molecular_function |
| Synonym | arachidonate:CoA ligase (AMP-forming); arachidonoyl-CoA synthetase activity |
| Definition | Catalysis of the reaction: arachidonate + ATP + CoA = AMP + arachidonoyl-CoA + diphosphate + H+. |
| Major function | Activation of arachidonic acid for eicosanoid synthesis and lipid metabolism |
| Substrate specificity | Prefers arachidonic acid (20:4) over other long-chain fatty acids |
| Inhibitors | Triacsin C differentially inhibits arachidonoyl-CoA synthetase |
| Tissue distribution | Platelets, brain microvessels, microvascular endothelium, and other tissues |
What Is GO:0047676?
Arachidonate-CoA ligase activity (GO:0047676) is defined as the catalysis of the reaction: arachidonate + ATP + CoA = AMP + arachidonoyl-CoA + diphosphate + H+. In other words, it is an enzyme activity that activates arachidonic acid by attaching it to coenzyme A, consuming ATP and releasing AMP and diphosphate. This activity is also known as arachidonoyl-CoA synthetase or arachidonate:CoA ligase (AMP-forming).
Why Is arachidonate-CoA ligase activity Important in Cell Biology?
Arachidonate-CoA ligase activity is essential for the metabolic activation of arachidonic acid, a key step in the production of eicosanoids that regulate inflammation, platelet aggregation, and vascular tone. Dysregulation of this activity has been implicated in various pathological conditions, including cardiovascular disease, neuroinflammation, and cancer. Understanding its mechanism and regulation provides insights into lipid signaling and offers potential therapeutic targets for modulating eicosanoid production.
• Initiates eicosanoid biosynthesis by converting arachidonate to arachidonoyl-CoA.
• Regulates platelet function and thromboxane A2 production.
• Involved in brain microvascular function and neuroinflammation.
• Differentially inhibited by triacsin C, enabling selective pharmacological studies.
• Exhibits strict fatty acid structural requirements, distinguishing it from nonspecific acyl-CoA synthetases.
• Linked to X-linked mental retardation through mutations in the related FACL4 gene.
• Plays a role in microvessel endothelial eicosanoid synthesis.
• Potential target for anti-inflammatory and anticancer therapies.
Molecular Mechanism of arachidonate-CoA ligase activity
Substrate Binding and Specificity
In simple terms: The enzyme grabs arachidonic acid and coenzyme A, using ATP as an energy source.
Arachidonate-CoA ligase activity exhibits high specificity for arachidonic acid (20:4) as a substrate, with structural requirements including a cis-double bond at the 5-position and a free carboxyl group. The enzyme binds arachidonate and CoA in an ordered manner, with ATP providing the energy for the ligation reaction. This specificity distinguishes it from nonspecific long-chain acyl-CoA synthetases that accept a broader range of fatty acids.
Catalytic Mechanism
In simple terms: The enzyme uses ATP to join arachidonic acid with CoA, producing arachidonoyl-CoA and byproducts.
The reaction proceeds via an acyl-adenylate intermediate, where arachidonate is first activated by ATP to form arachidonoyl-AMP, releasing diphosphate. The activated acyl group is then transferred to coenzyme A, yielding arachidonoyl-CoA and AMP. This two-step mechanism is characteristic of the ANL superfamily of enzymes and requires magnesium ions as cofactors.
Cofactors and Energetics
In simple terms: The reaction needs ATP and magnesium to work.
ATP is essential as the energy source, and magnesium ions (Mg2+) are required for ATP binding and catalysis. The reaction consumes one molecule of ATP per molecule of arachidonoyl-CoA formed, releasing AMP and diphosphate as byproducts.
Regulation and Inhibition
In simple terms: Certain chemicals can block this enzyme, and its activity can be regulated by cellular conditions.
Triacsin C is a differential inhibitor that selectively inhibits arachidonoyl-CoA synthetase over nonspecific long-chain acyl-CoA synthetase, making it a valuable tool for distinguishing between these activities. Glucocorticoids do not affect arachidonoyl-CoA synthetase activity in microvessel endothelium, suggesting that regulation occurs through other pathways. The enzyme's activity may also be modulated by substrate availability and post-translational modifications, though specific mechanisms remain to be fully elucidated.
Key Genes Involved in GO:0047676 arachidonate-CoA ligase activity
The following genes and proteins are associated with arachidonate-CoA ligase activity or related fatty acid activation pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACSL4 (FACL4) | Fatty acid-CoA ligase 4; activates arachidonic acid and other long-chain fatty acids | Mutations cause nonspecific X-linked mental retardation; involved in lipid metabolism and cancer |
| ACSL1 | Long-chain acyl-CoA synthetase 1; activates various fatty acids | Contributes to arachidonoyl-CoA synthetase activity in some tissues |
| ACSL3 | Long-chain acyl-CoA synthetase 3 | May contribute to arachidonate activation in specific cell types |
| ACSL5 | Long-chain acyl-CoA synthetase 5 | Potential role in arachidonic acid metabolism |
| ACSL6 | Long-chain acyl-CoA synthetase 6 | Expressed in brain; may activate arachidonic acid |
| SLC27A1 | Fatty acid transport protein 1 | Facilitates arachidonic acid uptake for activation |
| SLC27A4 | Fatty acid transport protein 4 | Involved in arachidonic acid transport |
| PLA2G4A | Cytosolic phospholipase A2 | Releases arachidonic acid from membrane phospholipids for activation |
| PTGS1 | Cyclooxygenase 1 | Converts arachidonoyl-CoA to prostaglandins |
| PTGS2 | Cyclooxygenase 2 | Inducible enzyme that uses arachidonic acid for eicosanoid synthesis |
| ALOX5 | 5-lipoxygenase | Metabolizes arachidonic acid to leukotrienes |
| TBXAS1 | Thromboxane A synthase 1 | Produces thromboxane A2 from arachidonic acid derivatives |
| CYP2J2 | Cytochrome P450 2J2 | Metabolizes arachidonic acid to epoxyeicosatrienoic acids |
| GPX4 | Glutathione peroxidase 4 | Regulates lipid peroxidation and interacts with ACSL4 |
| LPCAT3 | Lysophosphatidylcholine acyltransferase 3 | Remodels phospholipids with arachidonic acid |
| ABHD12 | Abhydrolase domain containing 12 | May regulate arachidonoyl-CoA levels |
| FAAH | Fatty acid amide hydrolase | Degrades anandamide and other arachidonic acid derivatives |
How Is arachidonate-CoA ligase activity Regulated?
Arachidonate-CoA ligase activity is regulated at multiple levels. Glucocorticoids do not affect arachidonoyl-CoA synthetase activity in microvessel endothelium, indicating that hormonal regulation may target downstream enzymes instead. Triacsin C acts as a differential inhibitor, selectively blocking arachidonoyl-CoA synthetase and providing a pharmacological means to modulate activity. Substrate availability, particularly the release of arachidonic acid by phospholipase A2, is a key regulatory step. Additionally, the enzyme's activity may be influenced by cellular energy status and the availability of coenzyme A and ATP.
arachidonate-CoA ligase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACSL4 (FACL4) | Nonspecific X-linked mental retardation | ACSL4 knockout or point-mutation knock-in in neuronal cell lines or mouse models |
| PTGS1/PTGS2 | Inflammation and cancer | Overexpression or knockout in cancer cell lines to study eicosanoid production |
| TBXAS1 | Cardiovascular disease | Platelet-specific knockout or overexpression models |
| ALOX5 | Asthma and inflammatory diseases | Knockout or point-mutation models in immune cells |
| GPX4 | Ferroptosis and cancer | ACSL4 knockout to study ferroptosis sensitivity |
Neurodevelopmental Disorders
Mutations in FACL4 (ACSL4), a gene encoding a fatty acid-CoA ligase, cause nonspecific X-linked mental retardation, highlighting the importance of arachidonoyl-CoA synthetase activity in brain development and function. The enzyme is present in brain microvessels, suggesting a role in maintaining the blood-brain barrier and neurovascular coupling.
Cardiovascular Disease
Arachidonoyl-CoA synthetase activity in platelets is critical for thromboxane A2 production, a potent vasoconstrictor and platelet aggregator. Dysregulation of this pathway contributes to thrombosis and atherosclerosis. The enzyme's presence in microvascular endothelium further links it to vascular inflammation and eicosanoid-mediated responses.
Cancer and Inflammation
Arachidonic acid metabolism is frequently upregulated in cancer, promoting cell proliferation and inflammation. Arachidonoyl-CoA synthetase provides the substrate for cyclooxygenases and lipoxygenases, which are often overexpressed in tumors. Inhibitors like triacsin C have been investigated for their potential to suppress cancer cell growth by blocking arachidonate activation.
From arachidonate-CoA ligase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ACSL4 mediate arachidonoyl-CoA synthetase activity in neurons? | ACSL4 knockout or point-mutation knock-in in neuronal cell lines |
| What is the role of arachidonoyl-CoA synthetase in platelet function? | Platelet-specific knockout of ACSL1 or ACSL4 in mouse models |
| How does triacsin C affect cancer cell proliferation? | Overexpression of arachidonoyl-CoA synthetase in cancer cell lines followed by triacsin C treatment |
| Does arachidonoyl-CoA synthetase regulate eicosanoid production in endothelium? | Endothelial-specific knockout of ACSL4 or ACSL1 |
| What are the structural requirements for substrate recognition? | Point mutations in the substrate-binding pocket of ACSL4 |
| Can arachidonoyl-CoA synthetase be targeted for anti-inflammatory therapy? | Knock-in of tagged ACSL4 for proteomic and imaging studies |
How to Study the arachidonate-CoA ligase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiometric enzyme assay | Arachidonoyl-CoA synthetase activity | Kinetic analysis and substrate specificity |
| Triacsin C inhibition | Differential inhibition of arachidonoyl-CoA synthetase | Distinguishing from nonspecific acyl-CoA synthetases |
| CRISPR knockout | Gene function in arachidonate activation | Identifying responsible enzymes in cell models |
| Lipidomics (LC-MS) | Arachidonoyl-CoA and eicosanoid levels | Pathway flux analysis in disease models |
| Western blot | Protein expression of ACSL isoforms | Validating knockout or overexpression |
| Immunofluorescence | Subcellular localization of ACSL enzymes | Tissue distribution studies |
| qRT-PCR | mRNA expression of ACSL genes | Comparing expression across tissues |
| Co-immunoprecipitation | Protein-protein interactions | Identifying regulatory partners |
Enzymatic Activity Assays
Arachidonoyl-CoA synthetase activity can be measured using radiometric assays with [14C]-arachidonic acid, followed by separation of arachidonoyl-CoA by thin-layer chromatography or HPLC. These assays are essential for determining kinetic parameters and substrate specificity.
Inhibitor Studies
Triacsin C is used to differentiate arachidonoyl-CoA synthetase from nonspecific long-chain acyl-CoA synthetase in cell lysates and intact cells. Dose-response curves and time-course experiments help establish the selectivity of inhibition.
Genetic Knockout and Knockdown
CRISPR-Cas9 knockout or siRNA knockdown of candidate genes such as ACSL4, ACSL1, or ACSL3 can be used to identify which enzymes contribute to arachidonoyl-CoA synthetase activity in a given cell type. Rescue experiments with wild-type or mutant constructs confirm specificity.
Lipidomics and Metabolomics
Mass spectrometry-based lipidomics can quantify arachidonoyl-CoA and downstream eicosanoids in cells and tissues, providing a comprehensive view of pathway flux. This approach is useful for studying the impact of genetic or pharmacological perturbations.
How CRISPR Can Be Used to Study GO:0047676 arachidonate-CoA ligase activity
Knockout
CRISPR-Cas9 knockout of ACSL4 or other candidate genes can abolish arachidonoyl-CoA synthetase activity in cell lines, allowing researchers to determine which enzyme is responsible for the activity in a specific context. Knockout models are also useful for studying the downstream effects on eicosanoid production and cellular phenotypes.
Point Mutation
Introducing point mutations in the catalytic domain or substrate-binding pocket of ACSL4 can help dissect the structural requirements for arachidonate recognition and catalysis. Such models are valuable for understanding how disease-associated mutations affect enzyme function.
Knock-in
Knock-in of tagged versions of ACSL4 (e.g., FLAG or GFP) enables affinity purification and imaging of the enzyme in its native context. This approach facilitates the study of protein interactions, subcellular localization, and post-translational modifications.
Overexpression
Overexpression of ACSL4 or other acyl-CoA synthetases in cell lines can amplify arachidonoyl-CoA synthetase activity, making it easier to measure and manipulate. Overexpression models are also used to study the effects of increased arachidonate activation on cell proliferation and eicosanoid production.
How EDITGENE Supports arachidonate-CoA ligase activity Research
Researchers studying arachidonate-CoA ligase activity-related genes often need to determine whether a candidate gene is causally involved in arachidonate activation, eicosanoid production, or related disease phenotypes. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for arachidonate-CoA ligase activity research.
Frequently Asked Questions About arachidonate-CoA ligase activity
What is arachidonate-CoA ligase activity?
Arachidonate-CoA ligase activity (GO:0047676) is an enzyme activity that catalyzes the ATP-dependent formation of arachidonoyl-CoA from arachidonate and coenzyme A, producing AMP and diphosphate as byproducts.
What genes are involved in arachidonate-CoA ligase activity?
Genes encoding fatty acid-CoA ligases such as ACSL4 (FACL4), ACSL1, and other ACSL family members are involved in arachidonoyl-CoA synthetase activity.
What is the reaction catalyzed by arachidonate-CoA ligase?
The reaction is: arachidonate + ATP + CoA = AMP + arachidonoyl-CoA + diphosphate + H+.
How is arachidonate-CoA ligase activity regulated?
It is regulated by substrate availability, cellular energy status, and can be inhibited by triacsin C; glucocorticoids do not affect the activity in microvessel endothelium.
What diseases are associated with arachidonate-CoA ligase activity?
Mutations in ACSL4 cause nonspecific X-linked mental retardation; the activity is also implicated in cardiovascular disease, inflammation, and cancer.
What is the difference between arachidonoyl-CoA synthetase and nonspecific acyl-CoA synthetase?
Arachidonoyl-CoA synthetase is specific for arachidonic acid and can be separated from nonspecific long-chain acyl-CoA synthetase by chromatographic methods and differential inhibition by triacsin C.
Which tissues express arachidonoyl-CoA synthetase?
It is present in human platelets, brain microvessels, microvascular endothelium, and various other cells and tissues.
What is triacsin C and how does it affect arachidonoyl-CoA synthetase?
Triacsin C is a differential inhibitor that selectively inhibits arachidonoyl-CoA synthetase over nonspecific long-chain acyl-CoA synthetase, making it a useful research tool.
Can CRISPR be used to study arachidonate-CoA ligase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be used to dissect the function of ACSL genes in arachidonate activation.
What methods measure arachidonoyl-CoA synthetase activity?
Radiometric enzyme assays with [14C]-arachidonic acid, HPLC, and mass spectrometry-based lipidomics are commonly used to measure arachidonoyl-CoA synthetase activity.
Conclusion
Arachidonate-CoA ligase activity (GO:0047676) is a critical enzymatic function that activates arachidonic acid for eicosanoid biosynthesis and lipid signaling. Its discovery in platelets and subsequent characterization in various tissues have established its importance in cardiovascular biology, neurodevelopment, and cancer. The enzyme's unique substrate specificity and differential inhibition by triacsin C provide valuable tools for researchers. Understanding the regulation and genetic basis of arachidonoyl-CoA synthetase activity may lead to new therapeutic strategies for inflammatory and metabolic diseases.
References
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- 6. Meloni I et al.. 2002. FACL4, encoding fatty acid-CoA ligase 4, is mutated in nonspecific X-linked mental retardation.. Nat Genet 30(4):436-40 PMID: 11889465
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