GO:0031836 neuromedin K receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031836 neuromedin K receptor binding is a molecular function describing the binding of a ligand to the neuromedin K receptor (NK3R), a G-protein-coupled receptor encoded by TACR3.
• The neuromedin K receptor is activated by the tachykinin peptide neurokinin B (NKB), and its binding properties have been characterized by mutational analysis.
• NK3R signaling is best known for its role in reproduction and has been implicated in sex-divergent effects on memory.
• Receptor binding sites for substance P, but not for substance K or neuromedin K, are expressed in arterioles, venules, and lymph nodules in inflammatory bowel disease, highlighting ligand-receptor specificity.
• The NK3R antagonist fezolinetant is approved for menopausal vasomotor symptoms, demonstrating the clinical relevance of this receptor system.
• Studying neuromedin K receptor binding requires tools such as radioligand binding assays, site-directed mutagenesis, and CRISPR-based gene editing to dissect ligand-receptor interactions.
Description
Neuromedin K receptor binding (GO:0031836) is a molecular function defined as the binding of a ligand to a neuromedin K receptor. The neuromedin K receptor, also known as neurokinin-3 receptor (NK3R), is a G-protein-coupled receptor that is activated by the tachykinin peptide neurokinin B (NKB). This receptor is encoded by the TACR3 gene and is part of the tachykinin receptor family, which also includes the substance P receptor (NK1R) and the substance K receptor (NK2R). The binding event is the first step in a signaling cascade that influences diverse physiological processes, including reproduction, memory, and vascular function. Researchers study neuromedin K receptor binding to understand how neurokinin B and synthetic ligands interact with NK3R at the molecular level. The binding affinity and specificity of these interactions are critical for drug development, as evidenced by the clinical use of NK3R antagonists such as fezolinetant for menopausal vasomotor symptoms. Moreover, the expression pattern of tachykinin receptor binding sites in inflammatory bowel disease suggests that these receptors may play a role in immune and vascular responses. The molecular function GO:0031836 is distinct from the broader processes of neuropeptide signaling and receptor activation. It specifically refers to the binding event itself, which can be measured experimentally using radioligand binding assays and studied through mutational analysis of the receptor. Understanding this function is essential for elucidating how neuromedin K and related peptides exert their effects and for designing targeted therapeutics.
neuromedin K receptor binding At A Glance
| GO ID | GO:0031836 |
|---|---|
| GO term | neuromedin K receptor binding |
| Ontology | molecular_function |
| Synonym | neurokinin-B receptor binding, neuromedin K receptor ligand |
| Definition | Binding to a neuromedin K receptor. |
| Major function | Mediates the interaction of neurokinin B and related peptides with the NK3R receptor, initiating signaling. |
| Related receptor | Neuromedin K receptor (NK3R), encoded by TACR3. |
| Endogenous ligand | Neurokinin B (NKB), a tachykinin peptide. |
| Experimental detection | Radioligand binding assays, mutational analysis, and receptor autoradiography. |
What Is GO:0031836?
In our own words, GO:0031836 neuromedin K receptor binding describes the molecular function of a ligand (such as the peptide neuromedin K, also known as neurokinin B) binding to a neuromedin K receptor. This binding is a non-covalent interaction between the ligand and the receptor protein, typically measured in vitro or in vivo. The term encompasses the ligand-receptor interaction that initiates downstream signaling, but it does not include the signaling events themselves. It is a child of the broader term 'neuropeptide receptor binding' and is specific to the neuromedin K receptor (NK3R).
Why Is neuromedin K receptor binding Important in Cell Biology?
Neuromedin K receptor binding is important because it is the initial molecular event that triggers NK3R-mediated signaling, which regulates key physiological processes such as reproduction, memory, and vascular tone. Dysregulation of this binding can contribute to diseases including inflammatory bowel disease and menopausal vasomotor symptoms, and the receptor is a validated drug target with approved antagonists like fezolinetant. Understanding the binding mechanism at atomic resolution aids in the design of selective ligands with improved efficacy and safety profiles.
• Neuromedin K receptor binding initiates signaling cascades that control gonadotropin-releasing hormone (GnRH) secretion and reproductive function.
• The receptor is a target for fezolinetant, an approved drug for menopausal hot flashes, highlighting its clinical relevance.
• NK3R blockade has sex-divergent effects on memory in mice, suggesting roles in cognitive processes.
• Binding sites for substance P, but not neuromedin K, are upregulated in inflammatory bowel disease, indicating ligand-specific roles in inflammation.
• Mutational analysis of NK3R has revealed key residues that determine binding affinity and selectivity.
• Radiolabeled NK3R ligands have been developed for imaging and diagnostic applications.
• The neuromedin K receptor is a member of the tachykinin receptor family, providing a model for studying GPCR-ligand interactions.
• Understanding neuromedin K receptor binding can inform the development of drugs for reproductive and neurological disorders.
Molecular Mechanism of neuromedin K receptor binding
Ligand recognition and binding pocket
In simple terms: The receptor has a pocket where the ligand fits, like a key in a lock.
The neuromedin K receptor (NK3R) binds neurokinin B (NKB) and related tachykinin peptides through a binding pocket formed by extracellular loops and transmembrane helices. Mutational analysis has identified specific residues that are critical for ligand recognition and binding affinity. The binding pocket is distinct from that of other tachykinin receptors, conferring selectivity for NKB over substance P and neurokinin A.
Conformational changes upon binding
In simple terms: When the ligand binds, the receptor changes shape to start a signal.
Ligand binding induces conformational changes in NK3R that lead to G-protein activation and downstream signaling. Although the exact conformational dynamics of NK3R are not fully resolved, studies of related GPCRs and mutational data suggest that binding triggers rearrangement of transmembrane helices. These changes are essential for coupling to Gq/11 proteins and initiating intracellular calcium release.
Binding specificity and affinity
In simple terms: The receptor prefers certain ligands over others, and binds them more or less tightly.
NK3R exhibits high affinity for neurokinin B and lower affinity for other tachykinins. Radioligand binding assays using selective NK3R ligands have quantified these affinities. The specificity is determined by the amino acid sequence of the receptor's binding pocket, as shown by site-directed mutagenesis. This specificity is crucial for physiological selectivity and drug design.
Regulation of binding by receptor availability
In simple terms: The amount of receptor on the cell surface affects how much binding can occur.
The binding of neuromedin K to its receptor is influenced by the expression level and trafficking of NK3R to the cell surface. Receptor internalization and desensitization following agonist exposure can reduce available binding sites. In inflammatory bowel disease, the expression of substance P binding sites, but not neuromedin K binding sites, is increased in vascular and lymphoid tissues, suggesting differential regulation of tachykinin receptor binding in disease.
Key Genes Involved in GO:0031836 neuromedin K receptor binding
The following genes and proteins are directly involved in neuromedin K receptor binding and its downstream signaling.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TACR3 | Encodes the neuromedin K receptor (NK3R), the primary binding target. | Central to studies of neurokinin B signaling and drug development. |
| TAC3 | Encodes neurokinin B (NKB), the endogenous ligand that binds NK3R. | Ligand for binding assays and physiological studies. |
| TAC1 | Encodes substance P, which binds NK1R but not NK3R with high affinity. | Used to demonstrate ligand specificity in binding studies. |
| TAC2 | Encodes neurokinin A, which binds NK2R but not NK3R with high affinity. | Control ligand for receptor selectivity experiments. |
| GNAQ | Encodes Gq alpha subunit, mediates signaling after NK3R activation. | Involved in downstream signaling following binding. |
| GNA11 | Encodes G11 alpha subunit, another G-protein coupled to NK3R. | Potential mediator of NK3R signaling. |
| ARRB1 | Beta-arrestin 1, regulates receptor desensitization and internalization. | Modulates binding availability and signaling. |
| ARRB2 | Beta-arrestin 2, regulates receptor trafficking. | Affects receptor recycling and binding capacity. |
| GRK2 | G-protein-coupled receptor kinase 2, phosphorylates activated NK3R. | Regulates desensitization after ligand binding. |
| GRK3 | G-protein-coupled receptor kinase 3, phosphorylates NK3R. | Contributes to receptor regulation. |
| KISS1R | Kisspeptin receptor, functionally interacts with NK3R in GnRH neurons. | Indirectly influences reproductive effects of NK3R binding. |
| GnRH1 | Gonadotropin-releasing hormone, downstream effector of NK3R signaling. | Links NK3R binding to reproductive physiology. |
| FOS | Immediate early gene, activated after NK3R stimulation. | Marker of neuronal activation following binding. |
| CREB1 | Transcription factor activated by NK3R signaling. | Mediates long-term effects of receptor binding. |
| MAPK1 | ERK2, downstream kinase in NK3R signaling. | Involved in cellular responses to binding. |
| MAPK3 | ERK1, downstream kinase in NK3R signaling. | Contributes to signaling cascades. |
| PLCB1 | Phospholipase C beta 1, generates IP3 and DAG after NK3R activation. | Key effector of Gq-mediated signaling. |
| PRKCA | Protein kinase C alpha, activated by DAG after NK3R binding. | Modulates downstream responses. |
How Is neuromedin K receptor binding Regulated?
The binding of neuromedin K to its receptor is regulated at multiple levels. Receptor expression levels, trafficking, and desensitization influence the availability of binding sites. Following agonist binding, G-protein-coupled receptor kinases (GRKs) phosphorylate the receptor, promoting beta-arrestin recruitment and internalization, which reduces surface binding sites. Additionally, the expression of TACR3 can be regulated by hormonal and developmental cues, affecting the capacity for neuromedin K binding. In disease states such as inflammatory bowel disease, the expression of tachykinin receptor binding sites can be differentially regulated, as shown by the selective upregulation of substance P binding sites but not neuromedin K binding sites in vascular and lymphoid tissues.
neuromedin K receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TACR3 | Hypogonadotropic hypogonadism, reproductive disorders | Tacr3 knockout mice, cell lines expressing mutant receptor |
| TAC3 | Hypogonadotropic hypogonadism | Tac3 knockout mice, ligand binding assays |
| TACR3 | Menopausal vasomotor symptoms | Ovariectomized rat models, NK3R antagonist treatment |
| TACR3 | Memory and cognitive function | Sex-specific behavioral tests in Nk3r knockout mice |
| TACR3 | Inflammatory bowel disease | Human tissue autoradiography, colitis mouse models |
Reproductive disorders
Neuromedin K receptor binding is critical for the regulation of GnRH secretion, and mutations in TACR3 or TAC3 can lead to hypogonadotropic hypogonadism. The receptor is a target for treating reproductive disorders, and its binding properties are studied to develop therapeutics.
Menopausal vasomotor symptoms
NK3R antagonists such as fezolinetant reduce hot flashes by blocking the binding of neurokinin B to NK3R. This clinical application underscores the importance of understanding neuromedin K receptor binding for drug development.
Inflammatory bowel disease
In surgical specimens from patients with ulcerative colitis and Crohn disease, binding sites for substance P, but not for substance K or neuromedin K, are expressed in high concentrations by arterioles, venules, and lymph nodules. This suggests that neuromedin K receptor binding is not upregulated in these inflammatory conditions, unlike NK1R binding.
Cognitive and memory functions
Nk3R blockade has sex-divergent effects on memory in mice, indicating that neuromedin K receptor binding may influence cognitive processes in a sex-specific manner.
From neuromedin K receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of TACR3 knockout on reproductive function? | Tacr3 knockout mouse |
| How do point mutations in TACR3 affect ligand binding affinity? | Site-directed mutagenesis and radioligand binding assays |
| Can a tagged NK3R be used to visualize receptor trafficking? | Knock-in mice expressing fluorescently tagged NK3R |
| What are the effects of NK3R overexpression in neurons? | Transgenic mice overexpressing TACR3 in specific brain regions |
| How does Nk3R blockade affect memory in males vs females? | Sex-specific behavioral studies in mice treated with NK3R antagonists |
| What is the binding specificity of novel NK3R ligands? | Competitive radioligand binding assays using cell membranes expressing NK3R |
How to Study the neuromedin K receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding assay | Binding affinity (Kd) and receptor density (Bmax) | Characterizing NK3R ligands and receptor expression |
| Site-directed mutagenesis | Effect of specific amino acid changes on binding | Mapping the ligand-binding pocket of NK3R |
| Autoradiography | Spatial distribution of receptor binding sites in tissues | Comparing receptor expression in health and disease |
| CRISPR knockout | Loss of receptor function | Studying physiological consequences of NK3R absence |
| CRISPR knock-in | Introduction of tagged or mutant receptor | Visualizing receptor trafficking and binding dynamics |
| Behavioral assays | Cognitive and reproductive outcomes | Assessing effects of NK3R blockade in vivo |
| Calcium imaging | Downstream signaling after ligand binding | Measuring NK3R activation in live cells |
| Competitive binding assay | Relative affinity of unlabeled ligands | Screening for selective NK3R antagonists |
Radioligand binding assays
Radioligand binding assays are the gold standard for measuring neuromedin K receptor binding. They use radiolabeled ligands such as [18F] or [11C] derivatives to quantify binding affinity and receptor density in tissues or cell membranes. These assays can be used to screen for novel ligands and to characterize receptor pharmacology.
Mutational analysis
Site-directed mutagenesis of the TACR3 gene allows researchers to identify amino acid residues critical for ligand binding. By expressing mutant receptors in heterologous systems and measuring binding, key determinants of specificity and affinity can be mapped.
Autoradiography
Receptor autoradiography using radiolabeled ligands can visualize the distribution of neuromedin K receptor binding sites in tissue sections. This technique has been used to show that neuromedin K binding sites are not upregulated in inflammatory bowel disease, unlike substance P binding sites.
CRISPR-based gene editing
CRISPR/Cas9 can be used to generate knockout, knock-in, or point-mutant cell lines and animal models to study the function of TACR3 and its binding properties. These models enable precise interrogation of the receptor's role in physiology and disease.
How CRISPR Can Be Used to Study GO:0031836 neuromedin K receptor binding
Knockout
CRISPR/Cas9-mediated knockout of TACR3 can generate cell lines or animal models lacking the neuromedin K receptor. These models are useful for studying the physiological consequences of loss of neuromedin K receptor binding, such as effects on reproduction and memory.
Point Mutation
Introducing specific point mutations into TACR3 via CRISPR can help dissect the contribution of individual amino acids to ligand binding. This approach complements traditional site-directed mutagenesis and allows study in a native genomic context.
Knock-in
Knock-in of a tagged or reporter gene into the TACR3 locus enables real-time visualization of receptor expression and trafficking. This can reveal how binding affects receptor internalization and recycling.
Overexpression
CRISPR activation (CRISPRa) or transgenic overexpression of TACR3 can be used to study the effects of increased receptor availability on ligand binding and downstream signaling. Overexpression models may reveal sensitization or desensitization phenomena.
How EDITGENE Supports neuromedin K receptor binding Research
Researchers studying neuromedin K receptor binding-related genes often need to determine whether a candidate gene is causally involved in receptor function, ligand specificity, or downstream signaling. EDITGENE provides a comprehensive suite of CRISPR-based services to create precisely engineered cell and animal models, enabling rigorous investigation of GO:0031836 and its associated pathways.
Contact EDITGENE today to design your custom CRISPR model for neuromedin K receptor binding research.
Frequently Asked Questions About neuromedin K receptor binding
What is GO:0031836 neuromedin K receptor binding?
GO:0031836 is a Gene Ontology molecular function term that describes the binding of a ligand to the neuromedin K receptor (NK3R), a G-protein-coupled receptor involved in neurokinin B signaling.
What genes are involved in neuromedin K receptor binding?
The primary gene is TACR3, which encodes the neuromedin K receptor. The ligand neurokinin B is encoded by TAC3. Other genes such as GNAQ, GNA11, and ARRB1 are involved in downstream signaling and regulation.
What is the function of the neuromedin K receptor?
The neuromedin K receptor (NK3R) binds neurokinin B and mediates signaling that regulates reproduction, memory, and vascular function. It is a target for drugs like fezolinetant.
How is neuromedin K receptor binding measured?
It is typically measured using radioligand binding assays with selective ligands, as well as mutational analysis and autoradiography.
What diseases are associated with neuromedin K receptor binding?
Dysregulation of NK3R binding is associated with hypogonadotropic hypogonadism, menopausal vasomotor symptoms, and possibly cognitive and inflammatory conditions.
What is the difference between neuromedin K receptor binding and neurokinin B signaling?
Neuromedin K receptor binding is the initial molecular event of ligand-receptor interaction, while neurokinin B signaling encompasses the downstream cellular responses that follow binding.
Can CRISPR be used to study neuromedin K receptor binding?
Yes, CRISPR knockout, knock-in, and point mutation models can be used to dissect the role of TACR3 and its binding properties in cells and animals.
What are the endogenous ligands for the neuromedin K receptor?
The primary endogenous ligand is neurokinin B (NKB), a tachykinin peptide encoded by TAC3. Other tachykinins like substance P and neurokinin A bind with lower affinity.
Is neuromedin K receptor binding involved in inflammatory bowel disease?
Studies show that binding sites for substance P, but not neuromedin K, are upregulated in arterioles, venules, and lymph nodules in inflammatory bowel disease, suggesting a different role for NK3R.
What drugs target neuromedin K receptor binding?
Fezolinetant is an approved NK3R antagonist that blocks neurokinin B binding and is used to treat menopausal vasomotor symptoms.
Conclusion
Neuromedin K receptor binding (GO:0031836) is a fundamental molecular function that initiates neurokinin B signaling through the NK3R receptor. Its study has revealed critical roles in reproduction, memory, and vascular biology, and has led to the development of clinically approved drugs like fezolinetant. Continued research using advanced CRISPR models and binding assays will further illuminate the therapeutic potential of targeting this interaction.
References
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