GO:0015964 diadenosine triphosphate catabolic process: Signaling Molecule Turnover, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0015964 describes the biochemical breakdown of diadenosine triphosphate (Ap3A), a dinucleotide polyphosphate alarmone.
• Ap3A is generated by aminoacyl-tRNA synthetases and ubiquitin-activating enzymes, linking it to translation and proteostasis [2, 8].
• Catabolism of Ap3A occurs extracellularly in endothelial cells and platelets, where it modulates vascular tone and platelet function [4, 7].
• The tumor suppressor Fhit is a major Ap3A hydrolase, and its loss elevates Ap3A levels, contributing to cancer progression.
• Dysregulated Ap3A catabolism is implicated in cardiovascular disease and cancer, making it a potential therapeutic target [6, 5].
• CRISPR knockout, knock-in, and overexpression models enable precise dissection of Ap3A catabolic enzymes in disease contexts.
Description
Diadenosine triphosphate (Ap3A) is a member of the dinucleotide polyphosphate family, which act as signaling molecules in various cellular processes. The catabolic process of Ap3A, annotated as GO:0015964, involves the enzymatic hydrolysis of this molecule into adenosine monophosphate and other derivatives, thereby terminating its signaling actions. This process is essential for maintaining cellular homeostasis and preventing the accumulation of potentially harmful alarmones. Understanding Ap3A catabolism is critical because dysregulation has been linked to cancer, cardiovascular disorders, and platelet dysfunction [5, 6]. The enzymes responsible for Ap3A breakdown, such as Fhit and ectonucleotidases, are subject to complex regulation and are emerging as targets for therapeutic intervention [5, 1]. This article provides a comprehensive overview of the molecular mechanisms, key genes, disease associations, and research methodologies pertinent to GO:0015964, with a focus on how CRISPR-based models can accelerate discovery in this field.
diadenosine triphosphate catabolic process At A Glance
| GO ID | GO:0015964 |
|---|---|
| GO term | diadenosine triphosphate catabolic process |
| Ontology | biological_process |
| Synonym | diadenosine triphosphate breakdown, diadenosine triphosphate catabolism, diadenosine triphosphate degradation |
| Major function | Breakdown of the alarmone diadenosine triphosphate (Ap3A) to regulate its signaling activity |
| Key enzymes | Fhit, ectonucleotidases (e.g., NTPDase1), and other hydrolases |
| Subcellular location | Extracellular space, cytoplasm, and platelet dense granules |
| Associated diseases | Cancer, cardiovascular disease, platelet disorders |
What Is GO:0015964?
GO:0015964, diadenosine triphosphate catabolic process, is defined as the chemical reactions and pathways resulting in the breakdown of diadenosine triphosphate (Ap3A), a derivative of the nucleoside adenosine with three phosphate groups attached. This process encompasses enzymatic hydrolysis that cleaves the phosphoanhydride bonds, ultimately yielding adenosine monophosphate (AMP) and other metabolites, thereby regulating the intracellular and extracellular levels of this signaling molecule.
Why Is diadenosine triphosphate catabolic process Important in Cell Biology?
The catabolism of diadenosine triphosphate is crucial for controlling the levels of this potent signaling molecule, which influences diverse physiological processes including vascular tone, platelet aggregation, and cell proliferation [1, 6]. Dysregulation of Ap3A breakdown can lead to its accumulation, which has been implicated in tumorigenesis and cardiovascular pathologies [5, 6]. Therefore, understanding the enzymes and regulatory mechanisms of GO:0015964 offers potential avenues for therapeutic intervention in cancer and thrombosis.
• Regulates intracellular and extracellular levels of the alarmone Ap3A.
• Modulates cardiovascular function, including vasodilation and platelet aggregation.
• Loss of Fhit, a key Ap3A hydrolase, is associated with many cancers.
• Ap3A accumulation can affect protein synthesis and stress responses.
• Enzymes of Ap3A catabolism are potential drug targets for thrombosis and cancer.
• Provides a mechanism for cross-talk between translation and signaling pathways.
• Involved in the extracellular nucleotide metabolism in endothelial cells.
• Ap3A and its catabolites can serve as biomarkers for platelet storage lesions.
What Happens During diadenosine triphosphate catabolic process?
Substrate recognition and binding
In simple terms: The enzyme grabs the Ap3A molecule.
The catabolic process begins with the specific recognition and binding of diadenosine triphosphate (Ap3A) by hydrolytic enzymes such as Fhit or ectonucleotidases [5, 1]. These enzymes possess active sites that accommodate the dinucleotide structure, positioning the phosphoanhydride bonds for cleavage. In endothelial cells, Ap3A is hydrolyzed by membrane-bound enzymes, indicating a role in extracellular signaling.
Hydrolytic cleavage of phosphoanhydride bonds
In simple terms: The enzyme cuts the bonds between phosphates, breaking Ap3A apart.
Following binding, the enzyme catalyzes the hydrolysis of the phosphoanhydride bonds in Ap3A, resulting in the formation of AMP and ADP, or other intermediates depending on the specific enzyme. Fhit, a diadenosine polyphosphate hydrolase, cleaves Ap3A into AMP and ADP, thereby terminating its signaling activity. This step is critical for regulating the intracellular concentration of Ap3A and preventing its accumulation.
Release of breakdown products
In simple terms: The pieces left over are released.
The breakdown products, primarily AMP and ADP, are released from the enzyme active site and can be further metabolized by other nucleotide pathways. These products can re-enter cellular metabolism or act as signaling molecules themselves. For example, AMP can be converted to adenosine, which has vasodilatory effects.
Regulation of enzyme activity
In simple terms: The process can be sped up or slowed down.
The activity of Ap3A-hydrolyzing enzymes is regulated at multiple levels, including gene expression, post-translational modifications, and interaction with inhibitors. For instance, small-molecule inhibitors of Fhit have been developed, highlighting the potential for pharmacological modulation. Additionally, the availability of substrates and the presence of divalent cations can influence enzyme activity.
Key Genes Involved in GO:0015964 diadenosine triphosphate catabolic process
The following genes and proteins are central to the catabolism of diadenosine triphosphate, as supported by published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FHIT | Diadenosine triphosphate hydrolase (Ap3A hydrolase) | Tumor suppressor, frequently lost in cancers; target for small-molecule inhibitors |
| NTPDase1 (ENTPD1) | Ectonucleotidase hydrolyzing Ap3A to AMP and ADP | Regulates extracellular nucleotide signaling in endothelial cells |
| NTPDase2 (ENTPD2) | Ectonucleotidase with preference for triphosphonucleosides | May contribute to Ap3A breakdown in specific tissues |
| NTPDase3 (ENTPD3) | Ectonucleotidase hydrolyzing Ap3A | Potential role in vascular and neuronal tissues |
| NTPDase8 (ENTPD8) | Ectonucleotidase | Expressed in liver and intestine, may metabolize Ap3A |
| AK1 | Adenylate kinase | Interconverts adenine nucleotides, indirectly affecting Ap3A levels |
| AK2 | Adenylate kinase | Mitochondrial isoform, may influence Ap3A catabolism |
| ADK | Adenosine kinase | Phosphorylates adenosine, affecting downstream metabolites |
| ADA | Adenosine deaminase | Degrades adenosine, influencing Ap3A catabolite fate |
| CD73 (NT5E) | Ecto-5'-nucleotidase | Converts AMP to adenosine, linking Ap3A catabolism to adenosine signaling |
| CD39 (ENTPD1) | Ectonucleoside triphosphate diphosphohydrolase | Hydrolyzes ATP and ADP, may also act on Ap3A |
| UBA1 | Ubiquitin-activating enzyme | Generates Ap3A as a byproduct, linking to proteostasis |
| UBA6 | Ubiquitin-like-activating enzyme | Produces Ap3A, connecting to ubiquitin-like pathways |
| LARS1 | Leucyl-tRNA synthetase | Generates Ap3A, linking translation to alarmone signaling |
| KARS1 | Lysyl-tRNA synthetase | Produces Ap3A, involved in translational quality control |
| HARS1 | Histidyl-tRNA synthetase | Synthesizes Ap3A, associated with neuropathy |
| AARS1 | Alanyl-tRNA synthetase | Generates Ap3A, implicated in Charcot-Marie-Tooth disease |
How Is diadenosine triphosphate catabolic process Regulated?
The catabolism of diadenosine triphosphate is regulated by the expression levels and activity of hydrolytic enzymes such as Fhit and ectonucleotidases [5, 1]. Fhit expression is frequently lost in cancer due to promoter hypermethylation or genomic deletions, leading to reduced Ap3A hydrolysis and accumulation of the alarmone. Additionally, the activity of ectonucleotidases can be modulated by extracellular nucleotide concentrations and inflammatory signals. Small-molecule inhibitors of Fhit have been identified, suggesting that pharmacological regulation of Ap3A catabolism is feasible. Furthermore, the generation of Ap3A by aminoacyl-tRNA synthetases and ubiquitin-activating enzymes links its catabolism to translation and proteostasis pathways, implying feedback regulation [2, 8].
diadenosine triphosphate catabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FHIT | Cancer (lung, breast, gastric) | Fhit knockout cell lines and mouse models; overexpression in cancer cells |
| ENTPD1 | Thrombosis, inflammation | Endothelial cell-specific knockout; point mutation of catalytic residues |
| LARS1 | Charcot-Marie-Tooth neuropathy | Knock-in of patient mutations; knockout in neuronal cells |
| HARS1 | Neurodegeneration | CRISPR knock-in of HARS1 mutations; overexpression studies |
| UBA1 | Proteostasis disorders | Knockout and point mutation to dissect Ap3A generation |
Cancer
Loss of Fhit, the major Ap3A hydrolase, is one of the most common genetic alterations in human cancers, including lung, breast, and gastric cancers. Reduced Fhit activity leads to elevated Ap3A levels, which may promote cell proliferation and survival through mechanisms involving the DNA damage response and apoptosis. Restoration of Fhit expression or inhibition of Ap3A signaling could be therapeutic strategies.
Cardiovascular disease
Diadenosine polyphosphates, including Ap3A, modulate vascular tone and platelet aggregation. Hydrolysis of Ap3A by endothelial ectonucleotidases regulates its bioavailability and thus its cardiovascular effects. Dysregulated Ap3A catabolism may contribute to thrombosis and hypertension, making enzymes like NTPDase1 potential targets [6, 4].
Platelet storage and function
Ap3A is stored in platelet dense granules and released upon activation. The catabolism of Ap3A in the extracellular space modulates platelet recruitment and thrombus formation. Alterations in Ap3A breakdown may affect platelet storage lesion and transfusion efficacy.
From diadenosine triphosphate catabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of FHIT increase Ap3A levels and promote tumorigenesis? | FHIT knockout cancer cell lines and xenografts |
| What is the catalytic mechanism of Fhit-mediated Ap3A hydrolysis? | Point mutations in the Fhit active site (e.g., H96N) followed by enzyme assays |
| How does NTPDase1 regulate extracellular Ap3A in endothelial cells? | Knock-in of tagged NTPDase1 for localization and activity studies |
| Can overexpression of Fhit suppress tumor growth? | Fhit overexpression in cancer cell lines and mouse models |
| What are the interactors of Ap3A in cancer cells? | Chemical proteomics with Ap3A probes in H1299 cells |
| Does Ap3A catabolism affect platelet function? | Platelet-specific knockout of ectonucleotidases; aggregation assays |
How to Study the diadenosine triphosphate catabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC | Ap3A and metabolite concentrations | Enzyme kinetics and inhibitor testing |
| Chemical proteomics | Protein interactors of Ap3A | Discovery of novel catabolic enzymes |
| CRISPR knockout screens | Genes affecting Ap3A sensitivity | Identification of synthetic lethal targets |
| Metabolomics (LC-MS) | Global nucleotide levels | Validation of genetic models |
| Western blot | Protein expression of Fhit, NTPDases | Assessing knockout efficiency |
| Immunofluorescence | Subcellular localization of enzymes | Studying extracellular vs intracellular catabolism |
| Platelet aggregation assays | Platelet function in response to Ap3A | Cardiovascular research |
| qRT-PCR | mRNA levels of catabolic genes | Gene expression analysis |
Enzymatic assays for Ap3A hydrolysis
Direct measurement of Ap3A catabolism can be performed using high-performance liquid chromatography (HPLC) or capillary electrophoresis to separate and quantify Ap3A and its breakdown products. Recombinant enzymes or cell lysates are incubated with Ap3A, and the reaction is monitored over time. This method is essential for characterizing the kinetic parameters of Fhit and ectonucleotidases.
Chemical proteomics to identify Ap3A interactors
Chemical proteomics using immobilized Ap3A probes can reveal novel binding proteins and enzymes involved in its catabolism. This approach has been applied in the cancer cell line H1299, identifying interactors that may regulate Ap3A signaling. Such methods provide unbiased discovery of the Ap3A interactome.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that modulate Ap3A levels or sensitivity to Ap3A-induced phenotypes. For example, screens in cancer cells with low Fhit expression can uncover synthetic lethal interactions. These screens are powerful for discovering new components of the catabolic pathway.
Metabolomics and nucleotide profiling
Mass spectrometry-based metabolomics allows comprehensive profiling of adenine nucleotides, including Ap3A, in cells and tissues. This method can quantify changes in Ap3A catabolism under different genetic or pharmacological conditions. It is particularly useful for validating knockout or overexpression models.
How CRISPR Can Be Used to Study GO:0015964 diadenosine triphosphate catabolic process
Knockout
CRISPR knockout of FHIT or ectonucleotidase genes (e.g., ENTPD1) in cell lines such as H1299 or endothelial cells can abolish Ap3A catabolism, leading to its accumulation [5, 4]. These models are used to study the consequences of Ap3A buildup on cell proliferation, apoptosis, and signaling pathways. Knockout models also serve as tools to validate the specificity of pharmacological inhibitors.
Point Mutation
Introducing point mutations in the catalytic residues of Fhit (e.g., H96N) or NTPDases via CRISPR can dissect the enzymatic mechanism of Ap3A hydrolysis. Such models help distinguish between catalytic activity and non-enzymatic functions of these proteins. Point mutations can also mimic naturally occurring variants associated with disease.
Knock-in
Knock-in of tagged versions of Fhit or NTPDases (e.g., GFP or HA tags) allows real-time tracking of enzyme localization and dynamics during Ap3A catabolism. Knock-in of disease-associated mutations, such as those in HARS1, can model neuropathy and study their impact on Ap3A metabolism. These models are valuable for understanding tissue-specific regulation.
Overexpression
Overexpression of Fhit or ectonucleotidases using CRISPR activation or lentiviral vectors can enhance Ap3A catabolism and suppress its signaling. This approach is used to test whether increasing Ap3A breakdown can reverse disease phenotypes, such as tumor growth or platelet hyperreactivity. Overexpression models also facilitate biochemical purification of the enzymes.
How EDITGENE Supports diadenosine triphosphate catabolic process Research
Researchers studying diadenosine triphosphate catabolic process-related genes often need to determine whether a candidate gene is causally involved in Ap3A turnover, and how its loss or gain of function affects cellular signaling and disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for diadenosine triphosphate catabolic process research.
Frequently Asked Questions About diadenosine triphosphate catabolic process
What is diadenosine triphosphate catabolic process?
It is the biochemical breakdown of diadenosine triphosphate (Ap3A), a signaling molecule, into AMP and other metabolites, as defined by GO:0015964.
What genes are involved in diadenosine triphosphate catabolic process?
Key genes include FHIT, ENTPD1, ENTPD2, ENTPD3, and ENTPD8, which encode enzymes that hydrolyze Ap3A [5, 4, 1].
How is diadenosine triphosphate catabolic process regulated?
It is regulated by the expression and activity of hydrolases like Fhit and ectonucleotidases, which can be modulated by genetic and pharmacological factors [5, 1].
What diseases are associated with diadenosine triphosphate catabolic process?
Dysregulation is linked to cancer, cardiovascular disease, and platelet disorders [5, 6, 7].
What is the role of Fhit in diadenosine triphosphate catabolic process?
Fhit is a tumor suppressor that hydrolyzes Ap3A; its loss leads to Ap3A accumulation and cancer progression.
How can CRISPR be used to study diadenosine triphosphate catabolic process?
CRISPR knockout, knock-in, and overexpression can create cell models to dissect the function of Ap3A catabolic enzymes [5, 4].
What are the substrates of diadenosine triphosphate catabolic process?
The primary substrate is diadenosine triphosphate (Ap3A), which is cleaved into AMP and ADP.
Where does diadenosine triphosphate catabolic process occur?
It occurs in various cellular compartments, including the extracellular space, cytoplasm, and platelet dense granules [4, 7].
What methods are used to study diadenosine triphosphate catabolic process?
Methods include HPLC, chemical proteomics, CRISPR screens, and metabolomics [4, 3, 5, 1].
Why is diadenosine triphosphate catabolic process important for cancer research?
Because Fhit loss and Ap3A accumulation are common in cancers, making this pathway a therapeutic target.
Conclusion
The catabolism of diadenosine triphosphate (GO:0015964) is a critical regulatory process that controls the levels of the alarmone Ap3A, influencing diverse physiological and pathological states [2, 5]. Key enzymes such as Fhit and ectonucleotidases are central to this process, and their dysregulation is implicated in cancer and cardiovascular disease [5, 6]. Advances in CRISPR-based models and chemical proteomics are accelerating our understanding of Ap3A catabolism and opening new avenues for therapeutic intervention [3, 5]. Continued research into this pathway holds promise for developing targeted treatments for diseases driven by aberrant Ap3A signaling.
References
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- 4. Goldman SJ et al.. 1986. Hydrolysis of diadenosine 5',5''-P',P''-triphosphate (Ap3A) by porcine aortic endothelial cells.. Circ Res 59(3):362-6 PMID: 3769150
- 5. Lange S et al.. 2017. Small-Molecule Inhibitors of the Tumor Suppressor Fhit.. Chembiochem 18(17):1707-1711 PMID: 28643453
- 6. Flores NA et al.. 1999. The effects of diadenosine polyphosphates on the cardiovascular system.. Cardiovasc Res 42(1):15-26 PMID: 10434992
- 7. Lüthje J et al.. 1983. The presence of diadenosine 5',5'''-P1,P3-triphosphate (Ap3A) in human platelets.. Biochem Biophys Res Commun 115(1):253-60 PMID: 6311204
- 8. Tshori S et al.. 2014. Amino-acyl tRNA synthetases generate dinucleotide polyphosphates as second messengers: functional implications.. Top Curr Chem 344:189-206 PMID: 23536246
