GO:0031685 adenosine receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031685 adenosine receptor binding is a molecular function defined as binding to an adenosine receptor, with the synonym adenosine receptor ligand.
• Adenosine receptor binding is mediated by adenosine and synthetic ligands such as xanthine derivatives, and it initiates downstream signaling through A1, A2A, A2B, and A3 receptors.
• Ligand binding at adenosine receptors can be biased, preferentially activating one signaling pathway over another, which is important for drug discovery.
• Altered adenosine receptor binding is observed in disease contexts including dystonia, coronary smooth muscle regulation, and the tumour immune microenvironment.
• Binding thermodynamics and structural mapping of receptor mutations provide mechanistic insight into ligand affinity and efficacy.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable causal testing of adenosine receptor binding in cells and animals.
Description
Adenosine receptor binding (GO:0031685) is the molecular function of selectively interacting with an adenosine receptor, a class of G protein-coupled receptors activated by the endogenous nucleoside adenosine. This binding event is the first step in a signaling cascade that regulates numerous physiological processes, including neurotransmission, vascular tone, inflammation, and immune responses. Because adenosine receptors are widely expressed and modulate both health and disease, understanding the molecular details of ligand binding is a central goal in pharmacology and drug discovery. Experimental studies have characterized adenosine receptor binding using radioligand binding assays, thermodynamic analyses, and structural mapping of receptor mutations. For example, binding of the A1 adenosine receptor ligand [3H]8-cyclopentyl-1,3-dipropylxanthine has been measured in coronary smooth muscle, linking receptor occupancy to functional responses. Similarly, xanthine derivatives have been evaluated for bronchospasmolytic activity and adenosine receptor binding, illustrating the therapeutic relevance of this molecular function. In disease, decreased adenosine receptor binding has been reported in dystonic brains of the dt(sz) mutant, suggesting a role in motor disorders. More recently, adenosine receptor binding has emerged as a key mechanism in the tumour immune microenvironment, where adenosine signaling suppresses antitumour immunity. Thus, GO:0031685 encompasses not only a biochemical interaction but also a critical control point for cellular signaling and disease intervention.
adenosine receptor binding At A Glance
| GO ID | GO:0031685 |
|---|---|
| GO term | adenosine receptor binding |
| Ontology | molecular_function |
| Synonym | adenosine receptor ligand |
| Major function | Binding to an adenosine receptor, initiating or modulating downstream signaling |
| Major ligands | Adenosine, xanthine derivatives, and other synthetic agonists/antagonists |
| Receptor subtypes | A1, A2A, A2B, and A3 adenosine receptors |
| Disease relevance | Dystonia, coronary smooth muscle regulation, tumour immune microenvironment |
| Research methods | Radioligand binding assays, thermodynamic analysis, structural mapping of mutations |
What Is GO:0031685?
In our own words, GO:0031685 adenosine receptor binding describes the selective, non-covalent interaction between a ligand (such as adenosine or a synthetic agonist/antagonist) and an adenosine receptor protein. This function is defined by the Gene Ontology as binding to an adenosine receptor, with the synonym adenosine receptor ligand. It is a molecular function that enables the ligand to occupy the receptor's orthosteric or allosteric site, thereby initiating or modulating downstream signaling.
Why Is adenosine receptor binding Important in Cell Biology?
Adenosine receptor binding is fundamentally important because it serves as the molecular switch that translates extracellular adenosine signals into intracellular responses, influencing processes as diverse as neurotransmission, vascular tone, inflammation, and tumour immunity. Dysregulation of this binding function is implicated in neurological disorders such as dystonia, in coronary smooth muscle physiology, and in cancer immune evasion. Moreover, the phenomenon of biased agonism at adenosine receptors means that different ligands can preferentially activate distinct signaling pathways, offering opportunities for safer and more selective therapeutics. Understanding the structural and thermodynamic basis of ligand binding, including how receptor mutations alter binding affinity and efficacy, is therefore essential for rational drug design.
• Adenosine receptor binding initiates signaling that regulates neurotransmission, vascular tone, and inflammation.
• Altered adenosine receptor binding is observed in dystonic brains, linking this function to motor disorders.
• Binding of A1 adenosine receptor ligands in coronary smooth muscle modulates cardiovascular function.
• Adenosine receptor binding in the tumour immune microenvironment contributes to immunosuppression and cancer progression.
• Biased agonism at adenosine receptors allows selective pathway activation, which is important for drug discovery.
• Thermodynamic characterization of binding at the human A3 adenosine receptor informs ligand design.
• Xanthine derivatives with adenosine receptor binding activity show bronchospasmolytic potential.
• Structural mapping of adenosine receptor mutations reveals how binding and signaling mechanisms are coupled.
• Modulation of protein kinase C by adenosine involves A1 receptor and pertussis toxin-sensitive G proteins, highlighting downstream effects of binding.
• CRISPR-based models enable causal testing of adenosine receptor binding in disease-relevant cell types.
Molecular Mechanism of adenosine receptor binding
Ligand recognition and orthosteric site occupancy
In simple terms: The ligand docks into a pocket on the adenosine receptor, like a key fitting a lock.
Adenosine receptor binding begins with recognition of the ligand by the receptor's orthosteric site. Structural mapping of adenosine receptor mutations has revealed key residues that determine ligand binding and signaling mechanisms. For example, xanthine derivatives have been shown to bind adenosine receptors with bronchospasmolytic activity, indicating that specific chemical features drive receptor occupancy. The binding event is selective for adenosine receptors and is the defining feature of GO:0031685.
Thermodynamic and kinetic aspects of binding
In simple terms: Binding strength and speed depend on energy changes when the ligand meets the receptor.
Binding thermodynamics at the human A3 adenosine receptor have been characterized, showing how enthalpy and entropy contribute to ligand affinity. Radioligand binding assays, such as those using [3H]8-cyclopentyl-1,3-dipropylxanthine, have quantified binding in coronary smooth muscle, providing kinetic and equilibrium parameters. These studies demonstrate that adenosine receptor binding is a dynamic process influenced by ligand structure and receptor environment.
Conformational changes and G protein coupling
In simple terms: Once the ligand binds, the receptor changes shape and activates G proteins inside the cell.
Ligand binding induces conformational changes in adenosine receptors that enable coupling to G proteins. Modulation of protein kinase C by adenosine involves the A1 receptor and a pertussis toxin-sensitive nucleotide binding protein system, indicating that binding triggers G protein-mediated signaling. Biased agonism at adenosine receptors further shows that different ligands can stabilize distinct receptor conformations, leading to preferential activation of certain pathways. Thus, binding is not merely a static interaction but a trigger for downstream signaling.
Allosteric modulation and receptor mutations
In simple terms: Other molecules or mutations can change how well the ligand binds.
Mutations in adenosine receptors can alter ligand binding and signaling, as revealed by structural mapping studies. Such mutations may affect the orthosteric site or allosteric networks, changing binding affinity or efficacy. This has implications for understanding disease-associated variants and for designing drugs that overcome resistance. Additionally, biased agonism can be influenced by receptor mutations, further complicating the binding-signaling relationship.
Binding in disease contexts
In simple terms: In some diseases, adenosine receptor binding is increased or decreased, affecting symptoms.
Decreased adenosine receptor binding has been observed in dystonic brains of the dt(sz) mutant, suggesting that altered binding contributes to motor dysfunction. In the tumour immune microenvironment, adenosine receptor binding promotes immunosuppression, and targeting this binding is a therapeutic strategy. These examples highlight that adenosine receptor binding is not only a biochemical event but also a disease-modifying function.
Key Genes Involved in GO:0031685 adenosine receptor binding
The following genes and proteins are central to adenosine receptor binding and its downstream effects.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ADORA1 | A1 adenosine receptor; binds adenosine and synthetic ligands | Mediates cardiac and neuronal effects; target for radioligand binding assays |
| ADORA2A | A2A adenosine receptor; binds adenosine | Involved in immune regulation and neurotransmission; biased agonism studies |
| ADORA2B | A2B adenosine receptor; binds adenosine | Linked to inflammation and tumour microenvironment |
| ADORA3 | A3 adenosine receptor; binds adenosine | Binding thermodynamics characterized; drug design target |
| GNAI1 | G protein alpha subunit; couples to A1 receptor | Pertussis toxin-sensitive signaling downstream of binding |
| GNAI2 | G protein alpha subunit; couples to adenosine receptors | Mediates inhibitory signaling after ligand binding |
| GNAI3 | G protein alpha subunit; couples to adenosine receptors | Participates in A1 receptor signaling |
| PRKCA | Protein kinase C alpha; modulated by adenosine | Downstream effector of adenosine receptor binding |
| PRKCB | Protein kinase C beta; modulated by adenosine | Downstream effector of adenosine receptor binding |
| PRKCG | Protein kinase C gamma; modulated by adenosine | Downstream effector of adenosine receptor binding |
| ENTPD1 | Ectonucleoside triphosphate diphosphohydrolase 1; produces adenosine | Regulates ligand availability for adenosine receptor binding |
| NT5E | Ecto-5'-nucleotidase; produces adenosine | Regulates adenosine levels and receptor binding |
| ADK | Adenosine kinase; metabolizes adenosine | Controls adenosine availability for receptor binding |
| SLC29A1 | Equilibrative nucleoside transporter 1; transports adenosine | Modulates extracellular adenosine for receptor binding |
| SLC29A2 | Equilibrative nucleoside transporter 2; transports adenosine | Modulates extracellular adenosine for receptor binding |
| IL6 | Interleukin 6; cytokine influenced by adenosine signaling | Readout of adenosine receptor binding in immune cells |
| TNF | Tumour necrosis factor; cytokine influenced by adenosine signaling | Readout of adenosine receptor binding in inflammation |
| VEGFA | Vascular endothelial growth factor A; influenced by adenosine | Downstream of adenosine receptor binding in tumour microenvironment |
How Is adenosine receptor binding Regulated?
Adenosine receptor binding is regulated at multiple levels. Ligand availability is controlled by enzymes such as CD39 (ENTPD1) and CD73 (NT5E), which generate adenosine, and by adenosine kinase (ADK) and nucleoside transporters (SLC29A1/A2), which remove or transport adenosine. Receptor expression levels and post-translational modifications can also influence binding capacity. Biased agonism provides a layer of regulation where different ligands stabilize distinct receptor conformations, leading to selective downstream signaling. Additionally, mutations in adenosine receptors can alter binding affinity and signaling, as shown by structural mapping. Downstream, protein kinase C modulation by adenosine via A1 receptor and pertussis toxin-sensitive G proteins represents a regulatory feedback mechanism.
adenosine receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ADORA1 | Dystonia; cardiovascular regulation | Adora1 knockout or point-mutation knock-in mice |
| ADORA2A | Neuroinflammation; tumour immunity | Adora2a knockout cell lines and syngeneic tumour models |
| ADORA2B | Tumour immune microenvironment; inflammation | Adora2b knockout or overexpression in immune cells |
| ADORA3 | Inflammation; cancer | Adora3 knockout or human A3 receptor knock-in for binding studies |
| NT5E | Cancer; immune suppression | NT5E knockout or overexpression to modulate adenosine availability |
Adenosine receptor binding in dystonia
Decreased adenosine receptor binding has been reported in dystonic brains of the dt(sz) mutant, suggesting that impaired adenosine signaling contributes to the pathophysiology of dystonia. This finding links GO:0031685 to motor disorders and supports further investigation of adenosine receptor ligands as potential therapeutics.
Adenosine receptor binding in cancer and tumour immunity
In the tumour immune microenvironment, adenosine receptor binding suppresses antitumour immune responses, promoting cancer progression. Targeting adenosine receptor binding, for example with antagonists, is an active area of immuno-oncology research. This highlights the importance of GO:0031685 in cancer biology and therapy.
Adenosine receptor binding in cardiovascular and respiratory systems
Binding of A1 adenosine receptor ligands in coronary smooth muscle modulates vascular tone, and xanthine derivatives with adenosine receptor binding activity show bronchospasmolytic effects. These studies indicate that adenosine receptor binding is relevant to cardiovascular and respiratory diseases.
Adenosine receptor binding in neurological and inflammatory conditions
Adenosine receptor binding influences neurotransmission and inflammation through A1 and A2A receptors, and biased agonism at these receptors may offer therapeutic selectivity. Modulation of protein kinase C by adenosine via A1 receptor signaling further connects binding to cellular stress and inflammatory pathways.
From adenosine receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ADORA1 affect adenosine receptor binding and signaling? | ADORA1 knockout cell line or mouse |
| How does a disease-associated mutation alter ligand binding? | Point-mutation knock-in of ADORA1/ADORA2A/ADORA3 |
| Can a specific ligand selectively activate one pathway? | Biased agonism assays in cells expressing wild-type vs mutant receptors |
| What is the role of adenosine receptor binding in tumour immunity? | ADORA2A/ADORA2B knockout in syngeneic tumour models |
| How does adenosine availability regulate receptor binding? | Knockout or overexpression of NT5E, ENTPD1, ADK, or SLC29A1/A2 |
| Can we visualize receptor binding in live cells? | Tagged knock-in of adenosine receptors with fluorescent or luminescent tags |
How to Study the adenosine receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding assay | Affinity and density of adenosine receptors | Characterizing ligands and receptor mutants |
| Isothermal titration calorimetry | Thermodynamic parameters of binding | Understanding driving forces of ligand recognition |
| Site-directed mutagenesis | Effect of specific residues on binding | Mapping binding pocket and signaling determinants |
| cAMP assay | G protein-mediated signaling after binding | Functional characterization of agonists/antagonists |
| Protein kinase C activity assay | Downstream effector activation | Measuring adenosine signaling via A1 receptor |
| Cytokine profiling | Immune response to adenosine receptor binding | Tumour microenvironment studies |
| Fluorescence/luminescence imaging | Receptor localization and binding dynamics | Live-cell visualization of tagged receptors |
| CRISPR knockout/knock-in | Causal role of genes in binding | Target validation and disease modeling |
Radioligand binding assays
Radioligand binding assays using tritiated ligands such as [3H]8-cyclopentyl-1,3-dipropylxanthine are classic methods to measure adenosine receptor binding affinity and density. These assays can be performed on membrane preparations from cells or tissues and are used to characterize competitive ligands.
Thermodynamic and kinetic analysis
Isothermal titration calorimetry and kinetic binding experiments provide thermodynamic parameters (enthalpy, entropy) and rate constants for adenosine receptor binding. Such analyses reveal the driving forces for ligand recognition and can guide drug design.
Structural and mutational mapping
Site-directed mutagenesis combined with binding assays and structural modeling maps the residues involved in adenosine receptor binding and signaling. This approach identifies how mutations alter ligand affinity and efficacy.
Functional signaling assays
Downstream signaling readouts, such as cAMP accumulation, protein kinase C activation, or cytokine production, measure the functional consequences of adenosine receptor binding. Biased agonism can be detected by comparing multiple pathways.
How CRISPR Can Be Used to Study GO:0031685 adenosine receptor binding
Knockout
CRISPR knockout of adenosine receptor genes (ADORA1, ADORA2A, ADORA2B, ADORA3) or adenosine-metabolizing enzymes (NT5E, ENTPD1, ADK) eliminates binding and downstream signaling, enabling causal tests of GO:0031685 in disease models. Knockout cell lines can be used in radioligand binding assays to confirm loss of binding.
Point Mutation
Point-mutation knock-in of specific residues in adenosine receptors can mimic disease-associated variants or alter ligand binding affinity, as informed by structural mapping studies. Such models help dissect the contribution of individual residues to binding and biased signaling.
Knock-in
Knock-in of tagged adenosine receptors (e.g., fluorescent or luminescent tags) allows real-time visualization of receptor binding and trafficking in live cells. Knock-in of human adenosine receptor genes into mouse models can humanize the receptor for drug testing.
Overexpression
Overexpression of adenosine receptors or adenosine-producing enzymes (NT5E, ENTPD1) increases binding capacity and can model disease states such as the tumour immune microenvironment. Overexpression systems are useful for high-throughput ligand screening and signaling studies.
How EDITGENE Supports adenosine receptor binding Research
Researchers studying adenosine receptor binding-related genes often need to determine whether a candidate gene is causally involved in ligand binding, receptor signaling, or disease progression. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell and animal models, enabling rigorous functional validation of GO:0031685 and its associated pathways.
Contact EDITGENE today to design your custom CRISPR model for adenosine receptor binding research.
Frequently Asked Questions About adenosine receptor binding
What is adenosine receptor binding?
Adenosine receptor binding (GO:0031685) is the molecular function of selectively interacting with an adenosine receptor, a G protein-coupled receptor activated by adenosine.
What genes are involved in adenosine receptor binding?
Key genes include ADORA1, ADORA2A, ADORA2B, and ADORA3, which encode the four adenosine receptor subtypes, as well as enzymes like NT5E and ENTPD1 that regulate adenosine availability.
What is the GO ID for adenosine receptor binding?
The Gene Ontology ID for adenosine receptor binding is GO:0031685.
What is the synonym for GO:0031685?
The synonym is adenosine receptor ligand.
How is adenosine receptor binding measured?
It is commonly measured by radioligand binding assays using tritiated ligands such as [3H]8-cyclopentyl-1,3-dipropylxanthine, as well as thermodynamic and functional assays.
What diseases are associated with adenosine receptor binding?
Altered adenosine receptor binding is implicated in dystonia, cardiovascular disorders, and the tumour immune microenvironment.
What is biased agonism at adenosine receptors?
Biased agonism is the ability of different ligands to preferentially activate distinct signaling pathways after binding to adenosine receptors.
How do mutations affect adenosine receptor binding?
Mutations in adenosine receptors can alter ligand binding affinity and signaling, as shown by structural mapping studies.
Can CRISPR be used to study adenosine receptor binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of adenosine receptor binding in cells and animals.
What cell models are available for adenosine receptor binding research?
EDITGENE provides knockout, point-mutation, knock-in, and overexpression cell models for adenosine receptor genes and related pathway enzymes.
Conclusion
Adenosine receptor binding (GO:0031685) is a fundamental molecular function that governs cellular responses to adenosine and synthetic ligands. Its role in neurotransmission, cardiovascular function, inflammation, and tumour immunity makes it a high-value target for basic and translational research. Understanding the structural, thermodynamic, and signaling aspects of this binding function, as well as its regulation and disease associations, requires robust experimental models. CRISPR-based approaches offer precise tools to dissect the causal roles of adenosine receptors and their ligands in health and disease.
References
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- 2. Gumber D et al.. 2020. Bronchospasmolytic activity and adenosine receptor binding of some newer 1,3-dipropyl-8-phenyl substituted xanthine derivatives.. Chem Biol Drug Des 95(6):600-609 PMID: 32100461
- 3. Marala RB et al.. 1995. Modulation of protein kinase C by adenosine: involvement of adenosine A1 receptor-pertussis toxin sensitive nucleotide binding protein system.. Mol Cell Biochem 149-150:51-8 PMID: 8569749
- 4. Han Y et al.. 2024. Unlocking the adenosine receptor mechanism of the tumour immune microenvironment.. Front Immunol 15:1434118 PMID: 38994361
- 5. McNeill SM et al.. 2021. Biased agonism at adenosine receptors.. Cell Signal 82:109954 PMID: 33610717
- 6. Nobrega JN et al.. 2005. Decreased adenosine receptor binding in dystonic brains of the dt(sz) mutant.. Neuroscience 134(1):33-8 PMID: 15961243
- 7. Merighi S et al.. 2002. Binding thermodynamics at the human A(3) adenosine receptor.. Biochem Pharmacol 63(2):157-61 PMID: 11841789
- 8. Hussain T et al.. 1995. Binding of A1 adenosine receptor ligand [3H]8-cyclopentyl-1,3-dipropylxanthine in coronary smooth muscle.. Circ Res 77(1):194-8 PMID: 7788877
