GO:0031702 type 1 angiotensin receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031702 (type 1 angiotensin receptor binding) is a molecular function defined as binding to a type 1 angiotensin receptor (AT1R).
• The term captures ligand-receptor interactions that initiate AT1R signaling, including binding by angiotensin II and related peptides.
• AT1R is a G protein-coupled receptor, but binding can also engage G protein-independent pathways such as beta-arrestin signaling.
• The renin-angiotensin system, including AT1R, is a major therapeutic target in hypertension and cardiovascular disease.
• AT1R has been implicated in COVID-19-associated pathologies and is studied as a gate towards disease states.
• Experimental models for this function include receptor binding assays, knockout and knock-in cell lines, and CRISPR-based editing.
Description
GO:0031702, type 1 angiotensin receptor binding, is a molecular function term that describes the binding of a ligand to a type 1 angiotensin receptor (AT1R). This interaction is central to the renin-angiotensin system, where angiotensin II and related peptides bind AT1R to trigger intracellular signaling. The term is distinct from receptor activity itself and focuses specifically on the binding event, which can be studied using biochemical and cellular assays. Understanding this function is important because AT1R is a key regulator of blood pressure, fluid balance, and cardiovascular homeostasis. Dysregulation of AT1R binding and signaling has been linked to hypertension, cardiovascular remodeling, and inflammatory conditions. Moreover, AT1R has emerged as a potential entry point for SARS-CoV-2-related pathologies, highlighting its broader relevance. Researchers studying GO:0031702 often need to determine which ligands bind AT1R, how binding affinity is modulated, and what downstream effects ensue. This article synthesizes authoritative QuickGO data and verified PubMed literature to provide a research-grade overview of the term, its mechanisms, associated genes, and experimental approaches.
type 1 angiotensin receptor binding At A Glance
| GO ID | GO:0031702 |
|---|---|
| GO term | type 1 angiotensin receptor binding |
| Ontology | molecular_function |
| Synonym | AT1 receptor binding, type 1 angiotensin receptor ligand |
| Definition | Binding to a type 1 angiotensin receptor. |
| Major function | Mediates ligand-receptor interaction initiating AT1R signaling. |
| Related receptor | Type 1 angiotensin II receptor (AT1R), a G protein-coupled receptor. |
| Major ligands | Angiotensin II, angiotensin-(1-9), des-aspartate-angiotensin I. |
| Therapeutic relevance | Target of angiotensin receptor blockers (ARBs) in hypertension. |
What Is GO:0031702?
According to the Gene Ontology, GO:0031702 (type 1 angiotensin receptor binding) is defined as the binding to a type 1 angiotensin receptor. In other words, it is the molecular function of a ligand or protein physically interacting with AT1R, without specifying the downstream signaling outcome. This binding event is a prerequisite for AT1R activation and can be measured experimentally using radioligand binding, surface plasmon resonance, or co-immunoprecipitation.
Why Is type 1 angiotensin receptor binding Important in Cell Biology?
GO:0031702 is important because AT1R binding is the first step in a signaling cascade that regulates blood pressure, electrolyte balance, and cardiovascular remodeling. Pharmacological blockade of AT1R with ARBs is a cornerstone of hypertension therapy, and understanding the binding function helps explain drug efficacy and resistance. Additionally, AT1R binding has been implicated in COVID-19-associated diseases, where the receptor may facilitate viral entry or exacerbate inflammation. Thus, studying this molecular function is critical for both basic biology and translational medicine.
• AT1R binding initiates vasoconstriction and aldosterone release, key to blood pressure control.
• ARBs target AT1R binding to treat hypertension and heart failure.
• AT1R binding can activate G protein-dependent and independent pathways, influencing cell growth and inflammation.
• The term is relevant to COVID-19 because AT1R is a potential gate for disease-associated complications.
• Angiotensin-(1-9) and des-aspartate-angiotensin I are alternative ligands that bind AT1R with distinct effects.
• Dysregulated AT1R binding contributes to cardiac hypertrophy and fibrosis.
• AT1R binding is studied in the context of hypoaldosteronism and adrenal disorders.
• The function is conserved across species, making animal models useful for research.
• CRISPR screens can identify modifiers of AT1R binding and signaling.
• Understanding binding specificity aids in designing biased ligands for safer therapies.
Molecular Mechanism of type 1 angiotensin receptor binding
Ligand recognition and binding pocket
In simple terms: The AT1R has a pocket where angiotensin peptides fit, like a key in a lock.
AT1R is a seven-transmembrane G protein-coupled receptor with a binding pocket formed by residues in the transmembrane helices and extracellular loops. Angiotensin II, the primary ligand, binds with high affinity, while angiotensin-(1-9) and des-aspartate-angiotensin I also interact with the receptor. The binding specificity is determined by ionic and hydrophobic interactions, and mutations in the pocket can alter ligand affinity.
Conformational changes and receptor activation
In simple terms: When the ligand binds, the receptor changes shape to send signals inside the cell.
Ligand binding induces conformational changes in AT1R, particularly in transmembrane helix 6 and 7, leading to activation of heterotrimeric G proteins (Gq/11) and subsequent phospholipase C signaling. This activation can also recruit beta-arrestins, which mediate G protein-independent signaling and receptor internalization. The balance between these pathways is influenced by the specific ligand and cellular context.
G protein-dependent signaling
In simple terms: The activated receptor turns on G proteins that increase calcium and other messengers.
Upon binding, AT1R acts as a guanine nucleotide exchange factor for Gq/11, leading to activation of phospholipase C, production of inositol trisphosphate and diacylglycerol, and release of intracellular calcium. This pathway is central to vasoconstriction and aldosterone secretion. G protein-dependent signaling is the classical pathway targeted by ARBs.
G protein-independent and biased signaling
In simple terms: The receptor can also signal without G proteins, through beta-arrestin.
AT1R can recruit beta-arrestin 1 and 2, which scaffold signaling complexes and activate pathways such as ERK1/2, Src, and Akt. This biased signaling can promote cell survival, proliferation, or migration, and may contribute to pathological remodeling. Ligands that selectively activate beta-arrestin pathways are being explored for therapeutic benefit.
Regulation by accessory proteins and post-translational modifications
In simple terms: Other proteins and chemical tags can tweak how well the receptor binds ligands.
AT1R function is modulated by post-translational modifications such as glycosylation and phosphorylation, and by interacting proteins like AT1R-associated protein (ATRAP). These modifications can affect ligand binding affinity, receptor stability, and trafficking. Additionally, the local renin-angiotensin system can regulate ligand availability.
Key Genes Involved in GO:0031702 type 1 angiotensin receptor binding
The following genes and proteins are directly or indirectly involved in type 1 angiotensin receptor binding and its downstream effects.
| Gene | Major Role | Research Relevance |
|---|---|---|
| AGTR1 | Encodes the type 1 angiotensin II receptor (AT1R) | Primary receptor for GO:0031702; target of ARBs |
| AGT | Angiotensinogen, precursor of angiotensin peptides | Provides ligands for AT1R binding |
| REN | Renin, catalyzes angiotensinogen cleavage | Rate-limiting step in angiotensin II production |
| ACE | Angiotensin-converting enzyme, generates angiotensin II | Regulates ligand availability for AT1R |
| ACE2 | Converts angiotensin II to angiotensin-(1-9) | Modulates AT1R binding by degrading ligand |
| AGTR2 | Type 2 angiotensin receptor | Counter-regulates AT1R effects |
| ARRB1 | Beta-arrestin 1 | Mediates G protein-independent AT1R signaling |
| ARRB2 | Beta-arrestin 2 | Mediates G protein-independent AT1R signaling |
| GNAQ | Gq alpha subunit | Couples AT1R to phospholipase C |
| GNA11 | G11 alpha subunit | Couples AT1R to phospholipase C |
| ATRAP | AT1R-associated protein | Negative regulator of AT1R signaling |
| CYP11B2 | Aldosterone synthase | Downstream effector of AT1R in adrenal gland |
| NOS3 | Endothelial nitric oxide synthase | Modulated by AT1R signaling |
| TGFB1 | Transforming growth factor beta 1 | Mediates AT1R-induced fibrosis |
| MAPK1 | ERK2 | Downstream kinase activated by AT1R |
| MAPK3 | ERK1 | Downstream kinase activated by AT1R |
| SRC | Proto-oncogene tyrosine-protein kinase Src | Mediates AT1R signaling to cytoskeleton |
| AKT1 | RAC-alpha serine/threonine-protein kinase | Survival signaling downstream of AT1R |
How Is type 1 angiotensin receptor binding Regulated?
The binding function of AT1R is regulated at multiple levels. Ligand availability is controlled by the renin-angiotensin system, including renin, ACE, and ACE2. Receptor expression and trafficking are influenced by post-translational modifications and interacting proteins such as ATRAP. Additionally, biased ligands can selectively stabilize conformations that favor G protein-dependent or beta-arrestin-dependent signaling. These regulatory mechanisms are critical for fine-tuning physiological responses and are targets for therapeutic intervention.
type 1 angiotensin receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| AGTR1 | Hypertension, cardiovascular remodeling | AGTR1 knockout or knock-in cell lines; ARB treatment |
| ACE2 | COVID-19 susceptibility, renin-angiotensin imbalance | ACE2 overexpression or knockout cells |
| CYP11B2 | Hypoaldosteronism | Adrenal cell models with CYP11B2 mutations |
| AGT | Hypertension, preeclampsia | AGT transgenic models |
| ARRB1 | Biased signaling in heart failure | ARRB1 knockout cells |
Hypertension and cardiovascular disease
AT1R binding and activation are central to the pathogenesis of hypertension. Angiotensin II binding to AT1R causes vasoconstriction and sodium retention, elevating blood pressure. ARBs block this interaction and are widely used to treat hypertension and heart failure. Dysregulated AT1R signaling also contributes to cardiac hypertrophy and fibrosis.
COVID-19-associated diseases
AT1R has been implicated in COVID-19-associated pathologies. The balance between ACE2 and AT1R may influence disease severity, and AT1R blockers are being investigated for potential benefits. The binding function of AT1R is relevant to understanding how SARS-CoV-2 infection perturbs the renin-angiotensin system.
Adrenal disorders and hypoaldosteronism
AT1R binding stimulates aldosterone production in the adrenal cortex. Defects in this pathway can lead to hypoaldosteronism, characterized by low aldosterone and electrolyte imbalances. Studying AT1R binding in adrenal cells can elucidate the molecular basis of such disorders.
From type 1 angiotensin receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does AGTR1 mediate angiotensin II-induced calcium flux? | AGTR1 knockout cell line (e.g., HEK293) |
| Which residues are critical for ligand binding? | Point-mutation knock-in of AGTR1 |
| Can a tagged AT1R be used for binding assays? | Knock-in of epitope-tagged AGTR1 |
| Does overexpression of AGTR1 enhance signaling? | AGTR1 overexpression cell line |
| What genes modify AT1R binding? | CRISPR library screening in AT1R-expressing cells |
| How does ACE2 affect AT1R binding? | ACE2 knockout or overexpression cells |
How to Study the type 1 angiotensin receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding | Ligand affinity and receptor density | Characterizing ARBs and ligands |
| Surface plasmon resonance | Kinetic constants (kon, koff) | Screening biased ligands |
| CRISPR knockout screen | Genes affecting AT1R binding | Identifying novel regulators |
| FRET/BRET | Conformational changes and protein interactions | Live-cell signaling studies |
| Immunoprecipitation | Protein-protein interactions | Detecting ATRAP-AT1R complexes |
| Calcium flux assay | Gq-mediated signaling | Functional readout of AT1R activation |
| Western blot | Downstream phosphorylation | Measuring ERK1/2 activation |
| RNA-seq | Transcriptional changes | Global effects of AT1R binding |
Radioligand binding assays
Radioligand binding assays using 125I-angiotensin II are the gold standard for measuring AT1R binding affinity and density. These assays can be performed on membrane preparations from cells or tissues and are used to characterize competitive antagonists like ARBs.
Surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC)
SPR and ITC provide real-time kinetic and thermodynamic data on AT1R-ligand interactions. These label-free methods can determine association and dissociation rates and are useful for studying biased ligands.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate AT1R binding or downstream signaling. Such screens have revealed modifiers of GPCR function and can be adapted for AT1R-specific pathways.
Fluorescence resonance energy transfer (FRET) and BRET
FRET and BRET biosensors can monitor AT1R conformational changes and interactions with G proteins or beta-arrestins in live cells. These techniques are valuable for studying the dynamics of binding and activation.
How CRISPR Can Be Used to Study GO:0031702 type 1 angiotensin receptor binding
Knockout
CRISPR knockout of AGTR1 eliminates AT1R expression, providing a clean background to study ligand binding specificity and downstream signaling. Knockout cells can be used in radioligand binding assays to confirm that binding is AT1R-specific.
Point Mutation
Point mutations in AGTR1 can be introduced to dissect the ligand-binding pocket and identify residues critical for angiotensin II binding. Such mutants help distinguish between G protein-dependent and independent signaling.
Knock-in
Knock-in of epitope-tagged or fluorescently tagged AT1R allows for real-time imaging and pull-down assays without altering endogenous regulation. Tagged receptors can be used in FRET/BRET studies to monitor conformational changes.
Overexpression
Overexpression of AGTR1 in cell lines can amplify signaling and binding signals for biochemical assays. However, overexpression may saturate pathways, so careful controls are needed.
How EDITGENE Supports type 1 angiotensin receptor binding Research
Researchers studying type 1 angiotensin receptor binding-related genes often need to determine whether a candidate gene is causally involved in ligand binding, receptor activation, or downstream signaling. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for type 1 angiotensin receptor binding research.
Frequently Asked Questions About type 1 angiotensin receptor binding
What is type 1 angiotensin receptor binding?
It is the molecular function defined by GO:0031702, describing the binding of a ligand to the type 1 angiotensin receptor (AT1R).
What genes are involved in type 1 angiotensin receptor binding?
Key genes include AGTR1 (encoding AT1R), AGT, REN, ACE, and ACE2, which regulate ligand availability and receptor function.
What is the role of AGTR1 in hypertension?
AGTR1 encodes AT1R; its binding to angiotensin II causes vasoconstriction and sodium retention, contributing to hypertension.
How is type 1 angiotensin receptor binding studied?
Common methods include radioligand binding assays, surface plasmon resonance, and CRISPR-based genetic screens.
What are angiotensin receptor blockers (ARBs)?
ARBs are drugs that block AT1R binding, used to treat hypertension and heart failure.
Is AT1R involved in COVID-19?
Yes, AT1R has been implicated in COVID-19-associated pathologies, and the renin-angiotensin system balance is relevant.
What is the difference between AT1R and AT2R?
AT1R (encoded by AGTR1) mediates most classical angiotensin II effects, while AT2R (AGTR2) often counter-regulates them.
Can CRISPR be used to study AT1R binding?
Yes, CRISPR knockout, knock-in, and point mutations in AGTR1 are powerful tools to dissect binding and signaling.
What is biased signaling at AT1R?
It refers to ligands that preferentially activate G protein-dependent or beta-arrestin-dependent pathways.
What diseases are linked to AT1R binding?
Hypertension, cardiovascular remodeling, COVID-19 complications, and hypoaldosteronism.
Conclusion
GO:0031702, type 1 angiotensin receptor binding, is a fundamental molecular function with broad implications for cardiovascular physiology and disease. Understanding the binding mechanism, associated genes, and regulatory pathways provides a foundation for therapeutic development. EDITGENE's CRISPR services empower researchers to dissect this function with precision and scale.
References
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- 3. Curnow KM. 1996. Human type-1 angiotensin II (AT1) receptor gene structure and function.. Clin Exp Pharmacol Physiol 23 Suppl 3:S67-73 PMID: 21143276
- 4. El-Arif G et al.. 2022. Angiotensin II Type I Receptor (AT1R): The Gate towards COVID-19-Associated Diseases.. Molecules 27(7) PMID: 35408447
- 5. Burnier M. 2001. Angiotensin II type 1 receptor blockers.. Circulation 103(6):904-12 PMID: 11171802
- 6. Polycarpe C et al.. 2026. Hypoaldosteronism.. PMID: 32310452
- 7. Curnow KM. 1996. Human type-1 angiotensin II (AT1) receptor gene structure and function.. Clin Exp Pharmacol Physiol Suppl 3:S67-73 PMID: 8993842
- 8. Sim MK. 2015. Des-aspartate-angiotensin I, a novel angiotensin AT(1) receptor drug.. Eur J Pharmacol 760:36-41 PMID: 25891368
