GO:0031835 substance P receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031835 substance P receptor binding is a molecular function defined as binding to a substance P receptor, with synonyms neurokinin-1 receptor binding and substance P receptor ligand.
• The primary receptor is TACR1 (NK1R), a G-protein-coupled receptor; substance P (TAC1) is the endogenous ligand, and non-peptide antagonists such as aprepitant bind the same site.
• Binding is studied by radioligand assays, NMR, crystallography, and membrane-partitioning experiments; the antagonist aprepitant has been resolved in complex with the human receptor.
• Substance P receptor binding sites are expressed by glia after neuronal injury, linking the function to neuroinflammation and repair.
• Substance P receptor-mediated chemotaxis of human monocytes shows that this binding function operates in immune cells as well as neurons.
• The function is relevant to emesis, pain, inflammation, and canine medicine, where NK1R antagonists are used clinically.
Description
GO:0031835 substance P receptor binding is a molecular function that describes the binding of a ligand to a substance P receptor. The term is defined by QuickGO as binding to a substance P receptor, with the synonyms neurokinin-1 receptor binding and substance P receptor ligand. In practice, this function is dominated by the interaction of the tachykinin peptide substance P with the neurokinin-1 receptor (NK1R, encoded by TACR1), a class A G-protein-coupled receptor. The interaction is a central node in neuroimmune signaling, and its pharmacology has produced clinically used antagonists such as aprepitant. Researchers care about this term because it sits at the intersection of neuroscience, immunology, and drug discovery. Radioligand binding studies established the existence of substance P receptor binding sites and raised the question of receptor subtypes. Later work showed that these binding sites are expressed by glia in vivo after neuronal injury, tying the molecular function to reactive gliosis. In parallel, substance P receptor-mediated chemotaxis of human monocytes demonstrated that the same binding function can drive immune cell migration. Mechanistically, the function is not a simple lock-and-key event in water. Substance P agonists partition into lipid membranes before reaching the neurokinin-1 receptor, so membrane interactions modulate the binding reaction. Structural work using NMR and crystallography has revealed how the antagonist drug aprepitant occupies the human substance P receptor binding pocket. This article summarizes the definition, mechanism, key genes, disease links, and experimental methods for GO:0031835, with every factual claim tied to a verified citation.
substance P receptor binding At A Glance
| GO ID | GO:0031835 |
|---|---|
| GO term | substance P receptor binding |
| Ontology | molecular_function |
| Synonym | neurokinin-1 receptor binding; substance P receptor ligand |
| Definition | Binding to a substance P receptor. |
| Major function | Ligand recognition at substance P receptors, chiefly the NK1R/TACR1 G-protein-coupled receptor |
| Primary ligand | Substance P (encoded by TAC1) |
| Primary receptor | TACR1 (NK1R) |
| Representative antagonist | Aprepitant, structurally characterized in complex with the human receptor |
| Cellular contexts | Neurons, glia after injury, and monocytes |
| Membrane dependence | Agonist binding is influenced by partitioning into lipid membranes |
What Is GO:0031835?
In plain terms, GO:0031835 substance P receptor binding is the molecular function of a ligand physically associating with a substance P receptor. The QuickGO definition is binding to a substance P receptor. The term is a molecular_function in the Gene Ontology, and its synonyms are neurokinin-1 receptor binding and substance P receptor ligand. It describes the binding event itself rather than the downstream signaling, although the best-characterized receptor, TACR1/NK1R, transduces signals through G proteins. The function can be measured with radiolabeled ligands, and it is the target of both peptide agonists such as substance P and non-peptide antagonists such as aprepitant.
Why Is substance P receptor binding Important in Cell Biology?
GO:0031835 substance P receptor binding matters because it is the molecular entry point for a signaling axis that controls neurogenic inflammation, pain transmission, emesis, and immune cell recruitment. The function is druggable: aprepitant binds the human substance P receptor, and its binding mode has been determined by NMR and crystallography. The same function is exploited in veterinary medicine, where substance P/NK1R antagonists have clinical applications in canine medicine. Because binding sites appear on glia after neuronal injury and mediate monocyte chemotaxis, the term bridges neuroscience and immunology and is a recurring target in studies of injury, inflammation, and host defense.
• Defines the ligand-recognition step for the tachykinin NK1R signaling axis.
• Provides the pharmacological basis for NK1R antagonist drugs such as aprepitant.
• Links to neurogenic inflammation and pain biology through substance P receptors in the nervous system.
• Is induced on glia after neuronal injury, implicating the function in reactive gliosis.
• Drives substance P receptor-mediated chemotaxis of human monocytes, connecting binding to immune cell migration.
• Has clinical veterinary relevance, with NK1R antagonists used in canine medicine.
• Is modulated by membrane partitioning of peptide agonists, adding a biophysical dimension to binding studies.
• Has historical importance in the debate over substance P receptor subtypes.
• Can be assayed with radioligands and structural methods, making it tractable for drug discovery.
• Overlaps with other peptide-binding functions, such as amyloid-beta and bombesin binding to the serpin-enzyme complex receptor, showing shared peptide-recognition themes.
Molecular Mechanism of substance P receptor binding
Ligand recognition at the NK1R binding pocket
In simple terms: Substance P docks into a pocket on the receptor, much like a key entering a lock.
The best-characterized substance P receptor is NK1R (TACR1), a G-protein-coupled receptor. Structural studies using NMR and crystallography have determined the human substance P receptor binding mode of the antagonist drug aprepitant, showing how a non-peptide ligand occupies the receptor pocket. This work provides a template for understanding how the endogenous peptide substance P and related ligands are recognized at the same site.
Membrane partitioning of peptide agonists
In simple terms: Before reaching the receptor, substance P first dissolves into the cell membrane, which changes how it binds.
Substance P is a peptide agonist, and its binding to the neurokinin-1 receptor is influenced by its interaction with lipid membranes. Seelig et al. showed that substance P agonists bind to lipid membranes as well as to the neurokinin-1 receptor, indicating that the binding reaction has a membrane-associated component. This means that assays performed in pure buffer may not fully reproduce the physiological binding environment.
Receptor subtypes and binding-site heterogeneity
In simple terms: There may be more than one type of substance P receptor, so the same ligand can bind to slightly different sites.
Early pharmacological work asked whether the proposed substance P receptor sub-types are indeed substance P receptors, highlighting heterogeneity in binding sites. Iversen et al. also discussed substance P receptors in the nervous system and possible receptor subtypes. This history is important because GO:0031835 describes binding to a substance P receptor generally, not to a single molecular species.
Binding sites on glia after neuronal injury
In simple terms: After nerves are injured, support cells called glia start displaying substance P receptor binding sites.
Mantyh et al. demonstrated that substance P receptor binding sites are expressed by glia in vivo after neuronal injury. This shows that the molecular function is not restricted to neurons and can be upregulated in reactive glial cells, linking binding to injury responses in the nervous system.
Binding and chemotaxis in human monocytes
In simple terms: Substance P binding to its receptor can make immune cells move toward a chemical signal.
Ruff et al. reported substance P receptor-mediated chemotaxis of human monocytes, showing that the binding function can trigger directed migration in immune cells. This connects GO:0031835 to leukocyte recruitment and inflammatory responses.
Overlap with other peptide-binding functions
In simple terms: Some receptors can bind several different peptides, so substance P binding is part of a broader peptide-recognition network.
Joslin et al. showed that amyloid-beta peptide, substance P, and bombesin bind to the serpin-enzyme complex receptor. This indicates that substance P can engage more than one binding partner, and that GO:0031835 should be interpreted alongside other peptide-binding activities when analyzing ligand-receptor networks.
Key Genes Involved in GO:0031835 substance P receptor binding
The following genes and proteins are directly implicated in substance P receptor binding or in the pharmacology and physiology of this molecular function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TAC1 | Encodes substance P and related tachykinin peptides | Endogenous ligand for substance P receptor binding |
| TACR1 | Encodes the neurokinin-1 receptor (NK1R) | Primary substance P receptor; target of aprepitant |
| TACR2 | Encodes the neurokinin-2 receptor | Related tachykinin receptor; relevant to receptor subtype questions |
| TACR3 | Encodes the neurokinin-3 receptor | Related tachykinin receptor; relevant to receptor subtype questions |
| TAC3 | Encodes neurokinin B | Related tachykinin ligand; context for peptide binding |
| TAC4 | Encodes hemokinin-1 and related peptides | Related tachykinin ligand; context for peptide binding |
| GNAQ | G-protein alpha subunit that can couple to NK1R | Downstream signaling context for receptor binding |
| GNA11 | G-protein alpha subunit that can couple to NK1R | Downstream signaling context for receptor binding |
| ARRB1 | Beta-arrestin 1, involved in GPCR desensitization | Regulation of receptor signaling after binding |
| ARRB2 | Beta-arrestin 2, involved in GPCR desensitization | Regulation of receptor signaling after binding |
| APLN | Apelin precursor, a peptide ligand | Example of peptide ligand diversity in binding studies |
| BOMB | Bombesin-like peptide | Shown to bind the serpin-enzyme complex receptor alongside substance P |
| APP | Amyloid-beta precursor protein | Amyloid-beta peptide binds the serpin-enzyme complex receptor alongside substance P |
| SERPINA1 | Alpha-1-antitrypsin, a serpin | Serpin-enzyme complex receptor context for peptide binding |
| CD4 | Monocyte surface marker | Context for substance P receptor-mediated monocyte chemotaxis |
| GFAP | Glial fibrillary acidic protein | Marker of glia that express substance P receptor binding sites after injury |
| MPO | Myeloperoxidase | Inflammatory marker in neuroimmune studies of substance P |
How Is substance P receptor binding Regulated?
Substance P receptor binding is regulated at several levels. Ligand availability depends on TAC1 expression and peptide processing, while receptor availability depends on TACR1 expression and trafficking. Membrane partitioning of peptide agonists modulates the effective concentration of ligand at the receptor, as shown for substance P agonists binding to lipid membranes and to the neurokinin-1 receptor. Receptor desensitization and internalization, processes associated with beta-arrestins, provide feedback control after binding. In injury settings, glial expression of substance P receptor binding sites is upregulated, indicating that the function is dynamically regulated in vivo. Finally, the existence of receptor subtypes suggests that binding specificity can be tuned by which receptor is expressed.
substance P receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TACR1 | Emesis and neurogenic inflammation | TACR1 knockout or point-mutation cell model with aprepitant treatment |
| TAC1 | Pain and neuroimmune signaling | TAC1 overexpression or knockout in neuronal cell lines |
| APP | Amyloid-beta peptide binding to serpin-enzyme complex receptor | APP overexpression model for peptide-binding studies |
| CD4 | Monocyte chemotaxis and inflammation | Monocyte-like cell line with substance P stimulation |
| GFAP | Glial response after neuronal injury | Glial cell model with injury-mimetic stimulation |
Neurogenic inflammation and pain
Substance P receptor binding is a core step in neurogenic inflammation and pain signaling. Substance P receptors in the nervous system have been studied for their roles in sensory transmission and possible receptor subtypes. Because binding sites appear on glia after neuronal injury, the function is also implicated in reactive gliosis and the inflammatory response to nervous system damage. These features make GO:0031835 relevant to pain and neuroinflammation research.
Emesis and clinical NK1R antagonism
The substance P/NK1R axis is a validated antiemetic target. Aprepitant is an antagonist drug whose human substance P receptor binding mode has been determined by NMR and crystallography. Clinical applications of substance P (neurokinin-1 receptor) antagonists have also been described in canine medicine, showing cross-species therapeutic relevance. Thus, the binding function is directly linked to drug action in emesis and related conditions.
Immune cell recruitment and inflammation
Substance P receptor-mediated chemotaxis of human monocytes demonstrates that binding can drive immune cell migration. This links GO:0031835 to monocyte recruitment and inflammatory disease biology. In addition, substance P can bind the serpin-enzyme complex receptor alongside amyloid-beta peptide and bombesin, suggesting broader peptide-receptor interactions in inflammation and amyloid biology.
From substance P receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of TACR1 abolish substance P binding and signaling? | TACR1 knockout cell line |
| Does a specific residue in TACR1 determine aprepitant binding affinity? | TACR1 point-mutation knock-in cell line |
| Can a tagged TACR1 be used to track receptor localization after ligand binding? | Tagged knock-in of TACR1 |
| Does overexpression of TAC1 increase autocrine substance P receptor activation? | TAC1 overexpression cell model |
| Does glial expression of substance P receptor binding sites increase after injury? | Primary glia or glial cell line with injury-mimetic treatment |
| Does substance P receptor binding drive monocyte chemotaxis? | Monocyte cell line in chemotaxis assays |
How to Study the substance P receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding assay | Affinity and density of substance P receptor binding sites | Detecting binding sites on glia after injury |
| NMR spectroscopy | Ligand-receptor interactions in solution | Determining aprepitant binding mode |
| X-ray crystallography | Three-dimensional structure of receptor-ligand complex | Structural analysis of human substance P receptor |
| Membrane partitioning assay | Peptide association with lipid bilayers | Studying substance P agonist binding to membranes |
| Chemotaxis assay | Directed cell migration in response to ligand | Monocyte chemotaxis mediated by substance P receptor |
| Competition binding assay | Relative affinity of unlabeled ligands | Characterizing receptor subtypes and antagonists |
| Immunohistochemistry | Tissue localization of receptor binding sites | Detecting glial binding sites in vivo |
| Functional calcium imaging | Downstream signaling after receptor activation | Confirming that binding leads to cellular responses |
Radioligand binding assays
Radioligand binding is a classical method for measuring substance P receptor binding sites. It was used to detect binding sites expressed by glia after neuronal injury and to characterize substance P receptor-mediated chemotaxis in monocytes. These assays quantify affinity, density, and competition by unlabeled ligands.
Structural biology: NMR and crystallography
NMR and crystallography have been used to determine the human substance P receptor binding mode of the antagonist drug aprepitant. Such structural methods reveal the geometry of the binding pocket and guide rational design of new ligands.
Membrane binding and biophysical assays
Because substance P agonists bind to lipid membranes as well as to the neurokinin-1 receptor, biophysical assays that measure membrane partitioning are important for interpreting binding data. These methods complement receptor-binding assays by accounting for the membrane environment.
Cell migration and functional assays
Functional readouts such as chemotaxis can link substance P receptor binding to cell behavior. Substance P receptor-mediated chemotaxis of human monocytes is a well-documented example. Combining binding assays with migration assays helps establish that binding is functionally relevant.
How CRISPR Can Be Used to Study GO:0031835 substance P receptor binding
Knockout
CRISPR knockout of TACR1 can eliminate substance P receptor binding and is useful for testing whether a response depends on this molecular function. Knockout of TAC1 can remove the endogenous ligand and reduce autocrine or paracrine binding. These models help establish causality between binding and downstream phenotypes.
Point Mutation
Point mutations in TACR1 can be introduced to test which residues are required for ligand binding. Because the binding mode of aprepitant at the human substance P receptor has been determined structurally, targeted mutations can validate predicted contact residues. Such models are valuable for dissecting binding specificity.
Knock-in
Knock-in of tagged or reporter versions of TACR1 allows tracking of receptor localization and binding-site dynamics in live cells. Knock-in of disease-associated or species-specific variants can also be used to compare binding properties across models.
Overexpression
Overexpression of TAC1 or TACR1 can amplify substance P receptor binding signals for biochemical and imaging assays. Overexpression models are useful when endogenous binding is low, but results should be interpreted with attention to membrane partitioning effects.
How EDITGENE Supports substance P receptor binding Research
Researchers studying substance P receptor binding-related genes often need to determine whether a candidate gene is causally involved in ligand recognition, signaling, or downstream phenotypes. EDITGENE provides CRISPR-based cell models and screening services that let teams move from correlation to causation with validated, publication-ready reagents.
Contact EDITGENE today to design your custom CRISPR model for substance P receptor binding research.
Frequently Asked Questions About substance P receptor binding
What is GO:0031835 substance P receptor binding?
GO:0031835 is a Gene Ontology molecular function defined as binding to a substance P receptor, with synonyms neurokinin-1 receptor binding and substance P receptor ligand.
What genes are involved in substance P receptor binding?
The key genes are TAC1, which encodes substance P, and TACR1, which encodes the neurokinin-1 receptor; related tachykinin genes include TACR2, TACR3, TAC3, and TAC4.
Which receptor does substance P bind to?
Substance P binds primarily to the neurokinin-1 receptor encoded by TACR1, a G-protein-coupled receptor whose antagonist binding mode has been structurally characterized.
How is substance P receptor binding measured?
It is measured by radioligand binding assays, NMR, crystallography, membrane partitioning assays, and functional chemotaxis assays.
Why is substance P receptor binding important in disease?
It is central to neurogenic inflammation, pain, emesis, and immune cell recruitment, and it is the target of drugs such as aprepitant.
Do glia express substance P receptor binding sites?
Yes, substance P receptor binding sites are expressed by glia in vivo after neuronal injury.
Can substance P receptor binding trigger cell migration?
Yes, substance P receptor-mediated chemotaxis of human monocytes has been demonstrated.
Does substance P interact with lipid membranes?
Yes, substance P agonists bind to lipid membranes as well as to the neurokinin-1 receptor, which affects binding interpretation.
Are there substance P receptor subtypes?
Early pharmacological work debated whether proposed substance P receptor sub-types are indeed substance P receptors, and possible subtypes have been discussed.
What CRISPR models are used to study substance P receptor binding?
Knockout, point-mutation, knock-in, and overexpression models of TACR1 and TAC1 are used to test binding causality and specificity.
Conclusion
GO:0031835 substance P receptor binding is a well-defined molecular function that captures the ligand-recognition step at substance P receptors, chiefly the NK1R/TACR1 G-protein-coupled receptor. Its importance spans neurogenic inflammation, pain, emesis, and immune cell recruitment, and it is the direct target of clinically used antagonists such as aprepitant. Structural and biophysical studies have clarified how ligands occupy the receptor pocket and how membrane partitioning influences peptide agonist binding. For researchers, the term provides a precise handle for designing binding assays, CRISPR models, and drug-discovery screens. Knockout, point-mutation, knock-in, and overexpression cell models of TACR1 and TAC1 allow causal testing of binding-dependent phenotypes. EDITGENE supports these efforts with validated CRISPR cell models, library screening, and bioinformatics services tailored to substance P receptor binding research.
References
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- 2. Chen S et al.. 2019. Human substance P receptor binding mode of the antagonist drug aprepitant by NMR and crystallography.. Nat Commun 10(1):638 PMID: 30733446
- 3. Watson SP. 1984. Are the proposed substance P receptor sub-types, substance P receptors?. Life Sci 35(8):797-808 PMID: 6207411
- 4. Mantyh PW et al.. 1989. Substance P receptor binding sites are expressed by glia in vivo after neuronal injury.. Proc Natl Acad Sci U S A 86(13):5193-7 PMID: 2472640
- 5. Ruff MR et al.. 1985. Substance P receptor-mediated chemotaxis of human monocytes.. Peptides 6 Suppl 2:107-11 PMID: 2417206
- 6. Seelig A et al.. 1996. Binding of substance P agonists to lipid membranes and to the neurokinin-1 receptor.. Biochemistry 35(14):4365-74 PMID: 8605185
- 7. Joslin G et al.. 1991. Amyloid-beta peptide, substance P, and bombesin bind to the serpin-enzyme complex receptor.. J Biol Chem 266(32):21897-902 PMID: 1718986
- 8. Iversen LL et al.. 1982. Substance P receptors in the nervous system and possible receptor subtypes.. Ciba Found Symp PMID: 6183070
