GO:0097004 adipokinetic hormone binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0097004 adipokinetic hormone binding describes the molecular function of selectively interacting with an adipokinetic hormone (AKH), a peptide hormone that mobilizes sugar and lipids from the insect fat body during energy-requiring activities such as flight and locomotion.
• AKH binding is mediated by the adipokinetic hormone receptor (AKHR), a class A G protein-coupled receptor (GPCR) that adopts an open conformation to facilitate hormone docking.
• The AKH/AKHR signalling axis is conserved across insects and regulates hemolymph sugar homeostasis, lipid mobilization, fecundity, and stress responses.
• Experimental binding studies using synthetic AKH analogs and receptor-binding assays have defined structure-activity relationships for the ligand-receptor interaction.
• In silico modelling and chemical models of binding have identified key residues and interaction surfaces in AKH and the related AKH/Corazonin-related peptide (ACP) systems.
• RNA-binding proteins that interact with AKH and glucagon mRNAs add an additional layer of post-transcriptional regulation to this signalling system.
Description
Adipokinetic hormone binding (GO:0097004) is a molecular function defined as the selective interaction with an adipokinetic hormone (AKH). AKHs are peptide hormones that are involved in the mobilization of sugar and lipids from the insect fat body during energy-requiring activities such as flight and locomotion, and they also contribute to hemolymph sugar homeostasis. This binding event is the first step in AKH signal transduction and is essential for the hormonal control of energy metabolism in insects. Researchers study this term to understand how insects coordinate fuel supply with behavioural and physiological demands, and to identify targets for pest control and for comparative endocrinology. The function is mediated primarily by the adipokinetic hormone receptor (AKHR), a G protein-coupled receptor (GPCR) that binds AKH with high specificity. Structural and chemical studies have shown that the receptor adopts an open conformation that facilitates hormone binding, and that specific residues in both the ligand and the receptor determine binding affinity and selectivity. Beyond the canonical receptor, RNA-binding proteins that interact with AKH mRNAs have been identified, suggesting that the availability of the hormone itself is regulated at the post-transcriptional level. Because AKH signalling is central to energy homeostasis, fecundity, and stress responses, adipokinetic hormone binding is a focal point for understanding insect physiology and for developing species-specific control strategies.
adipokinetic hormone binding At A Glance
| GO ID | GO:0097004 |
|---|---|
| GO term | adipokinetic hormone binding |
| Ontology | molecular_function |
| Synonym | AKH binding |
| Definition | Binding to an adipokinetic hormone. Adipokinetic hormones (AKHs) are peptide hormones that are involved in the mobilization of sugar and lipids from the insect fat body during energy-requiring activities such as flight and locomotion. They also contribute to hemolymph sugar homeostasis. |
| Major function | Selective interaction with AKH peptides to initiate hormonal signalling for energy mobilization and hemolymph sugar homeostasis. |
| Primary receptor | Adipokinetic hormone receptor (AKHR), a class A G protein-coupled receptor. |
| Taxonomic scope | Insects, including mosquitoes, fruit flies, stick insects, and psyllids. |
| Related peptides | Adipokinetic hormone/Corazonin-related peptide (ACP) system. |
What Is GO:0097004?
In our own words, GO:0097004 adipokinetic hormone binding is the molecular function of a protein or protein complex selectively and non-covalently interacting with an adipokinetic hormone (AKH). AKHs are insect peptide hormones that mobilize sugar and lipids from the fat body during energy-requiring activities such as flight and locomotion, and they also contribute to hemolymph sugar homeostasis. The binding event is the initial step in AKH signalling and is typically mediated by the adipokinetic hormone receptor (AKHR), a class A GPCR. The term is used in annotation to capture the ligand-binding activity itself, distinct from downstream signal transduction or metabolic outcomes.
Why Is adipokinetic hormone binding Important in Cell Biology?
Adipokinetic hormone binding is important because it is the molecular gateway for a hormonal system that controls energy homeostasis in insects. AKH peptides mobilize trehalose and lipids from the fat body during flight and locomotion, and they regulate hemolymph sugar levels. Disruption of AKH binding therefore affects flight capacity, stress tolerance, and reproduction, as shown by studies on AKH-producing cells and on AKH signalling in disease-vector insects. Because AKH signalling is specific to insects and related arthropods, the binding interface is also a promising target for biorational pesticides that could reduce vector populations or crop pests without affecting vertebrates. Understanding the structural basis of AKH binding, including the open conformation of the receptor and the role of specific residues, enables rational design of agonists and antagonists. Finally, the discovery of RNA-binding proteins that interact with AKH mRNAs highlights additional regulatory layers that could be exploited experimentally.
• Controls mobilization of sugar and lipids from the insect fat body during flight and locomotion.
• Maintains hemolymph sugar homeostasis, a critical physiological parameter in insects.
• Regulates fecundity, as shown in Diaphorina citri infected with 'Candidatus Liberibacter asiaticus'.
• Modulates metabolism, activity, and stress responses through AKH-producing cells.
• Provides a species-specific target for pesticide development against insect pests and disease vectors.
• Serves as a model for understanding class A GPCR ligand recognition and activation.
• Informs comparative endocrinology of energy-balance hormones across arthropods.
• Reveals post-transcriptional regulation through RNA-binding proteins interacting with AKH mRNAs.
• Supports structure-activity relationship studies using synthetic AKH analogs.
• Enables chemical modelling of binding for the AKH and ACP signalling systems.
Molecular Mechanism of adipokinetic hormone binding
Ligand recognition and receptor conformation
In simple terms: The receptor must be in the right shape to catch the hormone.
Adipokinetic hormone binding begins with the interaction between an AKH peptide and its receptor, AKHR. Molecular modelling of the AKHR from the malaria mosquito Anopheles gambiae indicates that the receptor adopts an open conformation that facilitates hormone binding. This open state exposes the binding pocket so that the hormone can enter and form stable contacts. The conformational flexibility of the receptor is therefore a key determinant of binding competence.
Chemical models of AKH and ACP binding
In simple terms: Scientists use chemical models to predict how the hormone fits into the receptor.
Chemical models of binding have been developed for the AKH and AKH/Corazonin-related peptide (ACP) signalling systems of the yellow fever mosquito Aedes aegypti. These models provide residue-level insights into how the peptides dock with their receptors and highlight differences between the AKH and ACP systems. Such models are useful for predicting binding affinities and for designing analogs with altered properties.
Structure-activity relationships from analog assays
In simple terms: Testing modified hormones shows which parts of the peptide are important for binding.
Analogs of Manduca adipokinetic hormone have been tested in both a bioassay and a receptor-binding assay, revealing which structural features of the peptide are required for effective binding. These studies demonstrate that even small modifications to the AKH sequence can alter receptor affinity, providing a foundation for understanding the molecular determinants of binding specificity.
Post-transcriptional regulation of hormone availability
In simple terms: RNA-binding proteins can control how much hormone mRNA is available to make protein.
The availability of AKH for binding is influenced by post-transcriptional mechanisms. Profiling of RNA-binding proteins that interact with glucagon and adipokinetic hormone mRNAs identified specific proteins that associate with these transcripts. This suggests that the abundance of AKH peptide, and therefore the extent of AKH binding, can be regulated at the level of mRNA stability or translation.
Physiological context of binding
In simple terms: Binding triggers a response that helps the insect meet its energy needs.
Once AKH binds to AKHR, the signal is transduced to mobilize trehalose and lipids from the fat body, supporting energy-requiring activities such as flight and locomotion. The intrinsic nutrient-sensing AKH-producing cells modulate metabolism, activity, and stress responses, integrating binding events with whole-body physiology. In Diaphorina citri, AKH signalling mediates enhanced fecundity upon infection with 'Candidatus Liberibacter asiaticus', showing that binding outcomes can be context-dependent.
Key Genes Involved in GO:0097004 adipokinetic hormone binding
The following genes and proteins are central to adipokinetic hormone binding and its downstream physiology.
| Gene | Major Role | Research Relevance |
|---|---|---|
| AKHR | Adipokinetic hormone receptor; binds AKH peptides | Primary receptor for GO:0097004; target for structural and pesticide studies |
| AKH | Adipokinetic hormone peptide ligand | Ligand whose binding to AKHR initiates signalling |
| ACP | Adipokinetic hormone/Corazonin-related peptide | Related peptide with its own binding system in mosquitoes |
| AKH-producing cells | Intrinsic nutrient-sensing cells that secrete AKH | Modulate metabolism, activity, and stress |
| RNA-binding proteins (unspecified) | Interact with AKH and glucagon mRNAs | Post-transcriptional regulation of hormone availability |
| Manduca AKH | Endogenous AKH of Manduca sexta | Used in analog binding assays |
| Anopheles gambiae AKHR | AKH receptor from malaria mosquito | Open conformation facilitates hormone binding |
| Aedes aegypti AKHR | AKH receptor from yellow fever mosquito | Chemical models of AKH and ACP binding |
| Carausius morosus AKHR | AKH receptor from stick insect | In silico characterization and pesticide screening |
| Diaphorina citri AKH | AKH signalling in Asian citrus psyllid | Mediates enhanced fecundity upon infection |
| Glucagon | Vertebrate hormone related to AKH | mRNA interacts with RNA-binding proteins |
| AKH/ACP receptor | Receptor for ACP | Part of the expanded AKH signalling system |
| Fat body | Tissue that responds to AKH | Site of sugar and lipid mobilization |
| Hemolymph | Circulatory fluid where sugar homeostasis occurs | Readout of AKH binding activity |
| Trehalose | Main hemolymph sugar mobilized by AKH | Metabolic endpoint of AKH binding |
| Lipids | Energy stores mobilized by AKH | Metabolic endpoint of AKH binding |
How Is adipokinetic hormone binding Regulated?
Adipokinetic hormone binding is regulated at multiple levels. The conformational state of the receptor controls whether it can bind hormone, as shown by the open conformation of the Anopheles gambiae AKHR that facilitates binding. The availability of the AKH peptide itself is subject to post-transcriptional regulation through RNA-binding proteins that interact with AKH mRNAs. In addition, the activity of AKH-producing cells is modulated by nutrient status, integrating binding capacity with metabolic demand. Physiological context, such as infection with 'Candidatus Liberibacter asiaticus' in Diaphorina citri, can also alter the functional outcome of AKH signalling.
adipokinetic hormone binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| AKH | Vector fecundity and pathogen transmission | Diaphorina citri infection model |
| AKHR | Pesticide target for insect control | Carausius morosus in silico and binding assays |
| AKH-producing cells | Metabolism, activity, and stress modulation | Drosophila or mosquito cell ablation |
| RNA-binding proteins | Post-transcriptional regulation of glucagon/AKH mRNAs | Cell-based RNA pull-down |
| ACP system | Mosquito neuropeptide signalling | Aedes aegypti chemical models |
Vector-borne disease transmission
Adipokinetic hormone binding is directly relevant to vector biology because AKH signalling influences fecundity and energy metabolism in mosquitoes and other disease vectors. In Diaphorina citri, the Asian citrus psyllid that transmits citrus greening disease, AKH signalling mediates enhanced fecundity upon infection with 'Candidatus Liberibacter asiaticus'. This link between AKH binding and reproductive output suggests that targeting the binding interface could reduce vector populations and thereby limit pathogen transmission.
Pesticide target potential
Because AKH binding is specific to insects and related arthropods, the AKH receptor is considered a promising target for biorational pesticides. In silico characterization of the AKH receptor from the stick insect Carausius morosus has been used to screen for pesticide candidates that interfere with hormone binding. Such approaches aim to disrupt energy homeostasis and flight capacity, providing a species-specific strategy for pest control.
Metabolic and stress-related physiology
Although AKH binding is not directly linked to a human disease, the underlying biology of energy mobilization has parallels with vertebrate glucagon signalling. RNA-binding proteins that interact with both glucagon and AKH mRNAs have been identified, indicating shared post-transcriptional regulatory mechanisms. Understanding these mechanisms in insects can inform comparative studies of metabolic regulation and stress responses in higher organisms.
From adipokinetic hormone binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of AKHR abolish AKH binding and downstream signalling? | AKHR knockout in insect cell lines or whole insects |
| Which residues in AKH are required for high-affinity binding? | Point mutations in AKH peptide or AKHR binding pocket |
| Can a tagged AKHR be used to visualize binding dynamics? | Knock-in of fluorescent or affinity tag at the AKHR locus |
| Does overexpression of AKHR increase hormone sensitivity? | Overexpression of AKHR in heterologous cells |
| How does infection alter AKH binding and fecundity? | Diaphorina citri infected with 'Candidatus Liberibacter asiaticus' |
| Can small molecules disrupt AKH binding? | High-throughput binding assays with synthetic analogs |
How to Study the adipokinetic hormone binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Receptor-binding assay | Direct binding affinity of AKH analogs | Structure-activity relationship studies |
| In silico docking | Predicted binding poses and energies | Receptor modelling and pesticide screening |
| Molecular dynamics | Conformational changes during binding | Open conformation of AKHR |
| RNA pull-down + mass spectrometry | RNA-binding proteins interacting with AKH mRNA | Post-transcriptional regulation |
| Hemolymph sugar assay | Trehalose levels as readout of AKH action | Physiological function of AKH binding |
| Lipid mobilization assay | Lipid release from fat body | Energy homeostasis studies |
| Fecundity assay | Reproductive output | Infection-mediated AKH signalling |
| Behavioural activity monitoring | Locomotion and stress responses | AKH-producing cell function |
Receptor-binding assays
Direct receptor-binding assays using radiolabeled or fluorescent AKH analogs are the gold standard for measuring adipokinetic hormone binding. Analogs of Manduca adipokinetic hormone have been tested in both bioassays and receptor-binding assays to determine affinity and specificity. These assays can be adapted for high-throughput screening of chemical libraries to identify compounds that compete with AKH for receptor occupancy.
In silico modelling and molecular dynamics
Computational approaches are widely used to study AKH binding because they can predict interaction surfaces and binding energies. Molecular models of the AKH and ACP systems in Aedes aegypti have been constructed to understand binding chemistry. Similarly, the open conformation of the Anopheles gambiae AKHR has been characterized in silico, revealing how receptor flexibility facilitates hormone binding. These methods are particularly useful when experimental structures are unavailable.
RNA interactome profiling
To study post-transcriptional regulation of AKH availability, RNA-binding proteins that interact with AKH and glucagon mRNAs can be profiled using RNA pull-down followed by mass spectrometry. This approach identified specific RNA-binding proteins associated with these transcripts. Such experiments link the binding function to upstream regulatory networks.
Physiological and behavioural assays
Because AKH binding ultimately affects energy mobilization, physiological assays measuring hemolymph sugar and lipid levels are essential. AKH-producing cells have been shown to modulate metabolism, activity, and stress responses, and these phenotypes can be quantified in vivo. In Diaphorina citri, fecundity measurements after infection provide a physiological readout of AKH signalling.
How CRISPR Can Be Used to Study GO:0097004 adipokinetic hormone binding
Knockout
CRISPR knockout of AKHR or AKH genes can definitively test the requirement for adipokinetic hormone binding in energy homeostasis and reproduction. Loss-of-function models would be expected to show impaired lipid mobilization and altered hemolymph sugar levels, based on the established role of AKH signalling. Such models are valuable for validating binding partners and for assessing the specificity of candidate pesticides.
Point Mutation
Point mutations in the AKH peptide or in the AKHR binding pocket can be introduced to map the residues that are critical for binding. This approach complements analog studies that have identified key structural features of Manduca AKH. CRISPR-mediated point mutations allow testing of these residues in the native genomic context, providing more physiologically relevant data than overexpression systems.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the AKHR locus enables real-time visualization of receptor localization and binding dynamics. Tagged receptors can be used in live-cell imaging to track hormone-induced internalization and trafficking. This strategy is particularly useful for studying the open conformation and ligand-induced conformational changes described for AKHR.
Overexpression
Overexpression of AKHR in heterologous cells or in insect tissues can increase sensitivity to AKH and amplify downstream signalling. This approach is useful for biochemical purification of the receptor and for high-throughput binding assays. Overexpression models can also reveal whether excess receptor leads to ligand-independent activation or altered metabolic phenotypes.
How EDITGENE Supports adipokinetic hormone binding Research
Researchers studying adipokinetic hormone binding-related genes often need to determine whether a candidate gene is causally involved in ligand recognition, signal transduction, or downstream metabolic outcomes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell and animal models for such studies.
Contact EDITGENE today to design your custom CRISPR model for adipokinetic hormone binding research.
Frequently Asked Questions About adipokinetic hormone binding
What is adipokinetic hormone binding?
Adipokinetic hormone binding (GO:0097004) is the molecular function of selectively interacting with an adipokinetic hormone (AKH), a peptide hormone that mobilizes sugar and lipids from the insect fat body during energy-requiring activities such as flight and locomotion, and contributes to hemolymph sugar homeostasis.
What genes are involved in adipokinetic hormone binding?
The primary gene is AKHR, which encodes the adipokinetic hormone receptor, a class A GPCR that binds AKH. Other relevant genes include AKH itself, the related ACP peptide, and RNA-binding proteins that interact with AKH mRNAs.
What is the GO ID for adipokinetic hormone binding?
The GO ID is GO:0097004, and the synonym is AKH binding.
How does AKH bind to its receptor?
AKH binds to the adipokinetic hormone receptor (AKHR), which adopts an open conformation that facilitates hormone binding. Chemical models have been developed for the AKH and ACP systems to understand the binding interface.
Why is adipokinetic hormone binding important for insects?
It controls the mobilization of sugar and lipids from the fat body during flight and locomotion, maintains hemolymph sugar homeostasis, and influences fecundity, metabolism, activity, and stress responses.
Can adipokinetic hormone binding be targeted for pest control?
Yes, because AKH signalling is specific to insects, the binding interface is considered a promising target for biorational pesticides. In silico screening has been used to identify pesticide candidates against the stick insect Carausius morosus.
What experimental methods are used to study AKH binding?
Common methods include receptor-binding assays with synthetic analogs, in silico docking and molecular dynamics, RNA pull-down for RNA-binding proteins, and physiological assays for hemolymph sugar and lipid levels.
Is adipokinetic hormone binding related to human disease?
AKH binding is not directly linked to human disease, but the underlying biology of energy mobilization has parallels with vertebrate glucagon signalling, and RNA-binding proteins interact with both glucagon and AKH mRNAs.
What model organisms are used to study adipokinetic hormone binding?
Model organisms include Aedes aegypti, Anopheles gambiae, Manduca sexta, Carausius morosus, and Diaphorina citri, each offering different experimental advantages.
How can CRISPR help study adipokinetic hormone binding?
CRISPR can generate knockouts, point mutations, knock-ins, and overexpression models for AKH, AKHR, and related genes, enabling precise functional studies of binding and downstream signalling.
Conclusion
Adipokinetic hormone binding (GO:0097004) is a well-defined molecular function that underpins a critical insect hormonal system for energy mobilization and homeostasis. The interaction between AKH peptides and the AKHR receptor has been characterized through structural modelling, chemical models, and analog binding assays, revealing key determinants of specificity and affinity. The physiological importance of this binding event extends to fecundity, stress responses, and vector competence, making it a compelling target for pest control and a model for comparative endocrinology. Continued research using CRISPR-based models and advanced binding assays will further elucidate the regulatory layers, including post-transcriptional control by RNA-binding proteins, that shape AKH signalling.
References
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- 5. Li J et al.. 2024. Adipokinetic hormone signaling mediates the enhanced fecundity of Diaphorina citri infected by 'Candidatus Liberibacter asiaticus'.. Elife 13 PMID: 38985571
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