GO:0031703 type 2 angiotensin receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031703 (type 2 angiotensin receptor binding) is a molecular function defined as binding to a type 2 angiotensin receptor (AT2R).
• AT2R is a G-protein-coupled receptor that can signal through Gi and is implicated in vasodilation, antiproliferation, and apoptosis [1,6,8].
• The AT2R binds angiotensin II and related peptides, and its binding properties are distinct from the AT1 receptor [3,7].
• AT2R is expressed in adult kidney and promotes cellular proliferation and apoptosis, linking it to renal and cardiovascular physiology.
• Dysregulation of AT2R signaling is associated with hypertension, renal disease, and cardiovascular remodeling [2,3].
• CRISPR-based models (knockout, knock-in, point mutation, overexpression) enable causal dissection of AT2R binding and signaling in disease [3,7].
Description
Type 2 angiotensin receptor binding (GO:0031703) is a molecular function that describes the binding of a ligand to the angiotensin II type 2 receptor (AT2R). AT2R is a seven-transmembrane G-protein-coupled receptor that is part of the renin-angiotensin system and is known to counter-regulate many effects of the angiotensin II type 1 receptor (AT1R) [1,3]. The binding event at AT2R is a critical initial step for downstream signaling that can lead to vasodilation, inhibition of cell proliferation, and promotion of apoptosis [1,6,8]. Understanding this binding function is essential for researchers studying cardiovascular and renal physiology, as well as for drug discovery targeting the renin-angiotensin system [2,3]. The AT2R is activated by angiotensin II and possibly by other peptides such as angiotensin-(1-9), and its binding characteristics have been studied in various tissues [2,7]. Unlike AT1R, AT2R can couple to Gi proteins, and its activation has been linked to bradykinin/nitric oxide pathways and phosphatase activation [1,6]. The receptor is expressed in adult kidney, where it promotes cellular proliferation and apoptosis, indicating a role in tissue remodeling. Thus, GO:0031703 represents a key molecular interaction that translates extracellular signals into diverse cellular outcomes. For researchers, GO:0031703 provides a precise annotation for experiments involving ligand-receptor binding assays, receptor mutagenesis, and functional studies. The term is particularly relevant for those using CRISPR gene editing to create knockout or knock-in models of AT2R and its ligands, as well as for those screening for compounds that modulate this binding [3,7]. As the renin-angiotensin system is a major therapeutic target, understanding the molecular details of AT2R binding can inform the development of novel drugs for hypertension and cardiovascular diseases [2,3].
type 2 angiotensin receptor binding At A Glance
| GO ID | GO:0031703 |
|---|---|
| GO term | type 2 angiotensin receptor binding |
| Ontology | molecular_function |
| Synonym | AT2 receptor binding, type 2 angiotensin receptor ligand |
| Major function | Binding to the angiotensin II type 2 receptor (AT2R), initiating downstream signaling [1,6] |
| Related receptor | Angiotensin II type 2 receptor (AT2R), a GPCR |
| Endogenous ligands | Angiotensin II, angiotensin-(1-9) [2,7] |
| Signaling pathway | Gi activation, vasodilation, antiproliferation, apoptosis [1,6,8] |
| Tissue expression | Adult kidney, cardiovascular tissues [3,8] |
What Is GO:0031703?
GO:0031703, type 2 angiotensin receptor binding, is defined as the binding to a type 2 angiotensin receptor. In other words, it is the molecular function of a ligand (such as angiotensin II or related peptides) physically interacting with the AT2R protein. This binding event is the first step in AT2R-mediated signaling and can be measured experimentally using radioligand binding assays, surface plasmon resonance, or other biophysical methods [1,7].
Why Is type 2 angiotensin receptor binding Important in Cell Biology?
GO:0031703 is important because the binding of ligands to AT2R is a key regulatory event in the renin-angiotensin system, which controls blood pressure, fluid balance, and cardiovascular remodeling. Dysregulation of this binding can contribute to hypertension, renal injury, and heart failure [2,3]. Moreover, AT2R has been proposed as a therapeutic target, and understanding its binding properties can aid in the design of drugs that selectively modulate this receptor.
• Regulates vasodilation and blood pressure through AT2R-mediated signaling.
• Counterbalances AT1R effects, influencing cardiovascular homeostasis.
• Promotes apoptosis and inhibits proliferation in renal cells.
• Involved in hypertension pathogenesis and potential therapy.
• Expressed in adult kidney, linking to renal disease.
• Target for drug discovery in cardiovascular medicine.
• Provides a molecular handle for CRISPR-based functional studies.
• Helps explain ligand selectivity between AT1R and AT2R.
Molecular Mechanism of type 2 angiotensin receptor binding
Ligand recognition and binding pocket
In simple terms: The AT2R has a pocket where angiotensin peptides fit, like a lock and key.
The AT2R binds angiotensin II and related peptides through a binding pocket formed by transmembrane helices. This binding is specific and can be studied using radioligand assays [1,7]. The receptor's affinity for ligands can be influenced by its conformational state and by interactions with other proteins.
Receptor activation and Gi coupling
In simple terms: Once the ligand binds, the receptor changes shape and activates G proteins inside the cell.
Ligand binding to AT2R induces conformational changes that allow coupling to Gi proteins, leading to inhibition of adenylyl cyclase and activation of downstream effectors. This Gi activation is a hallmark of AT2R signaling and distinguishes it from AT1R, which primarily couples to Gq [1,3].
Downstream signaling cascades
In simple terms: The activated receptor triggers a chain of events that can make blood vessels relax or cells die.
AT2R activation can lead to vasodilation via bradykinin/nitric oxide pathways and to apoptosis through phosphatase activation [1,8]. These effects are context-dependent and can vary by tissue and cell type.
Regulation by heterodimerization and interacting proteins
In simple terms: The receptor can team up with other proteins, which changes how it works.
AT2R can heterodimerize with other receptors, such as the AT1R, and this interaction can modulate its binding and signaling properties. Additionally, AT2R function can be regulated by β-arrestins and other intracellular proteins.
Key Genes Involved in GO:0031703 type 2 angiotensin receptor binding
The following genes and proteins are directly involved in type 2 angiotensin receptor binding and its downstream effects.
| Gene | Major Role | Research Relevance |
|---|---|---|
| AGTR2 | Encodes the AT2R, the receptor that binds angiotensin II and related peptides | Central to GO:0031703; target for knockout and knock-in studies [1,3] |
| AGT | Encodes angiotensinogen, the precursor of angiotensin peptides | Provides ligands for AT2R binding; relevant for overexpression models |
| REN | Encodes renin, which cleaves angiotensinogen to generate angiotensin I | Upstream of ligand production; can be manipulated in cell models |
| ACE | Encodes angiotensin-converting enzyme, which generates angiotensin II | Affects ligand availability for AT2R binding |
| ACE2 | Encodes angiotensin-converting enzyme 2, which generates angiotensin-(1-9) | Produces alternative ligand for AT2R |
| AGTR1 | Encodes the AT1R, which can heterodimerize with AT2R | Modulates AT2R binding and signaling |
| GNAI1 | Encodes Gi alpha subunit, involved in AT2R signaling | Mediates downstream effects of AT2R activation |
| GNAI2 | Encodes another Gi alpha subunit | Potential mediator of AT2R signaling |
| GNAI3 | Encodes Gi alpha subunit | May contribute to AT2R signaling |
| ARRB1 | Encodes β-arrestin 1, which can regulate GPCR trafficking | Modulates AT2R desensitization and internalization |
| ARRB2 | Encodes β-arrestin 2 | Regulates AT2R signaling and binding |
| BDKRB2 | Encodes bradykinin receptor B2, involved in AT2R-mediated vasodilation | Downstream effector of AT2R |
| NOS3 | Encodes endothelial nitric oxide synthase, producing NO | Mediates vasodilation downstream of AT2R |
| PTPN6 | Encodes SHP-1 phosphatase, involved in AT2R-mediated apoptosis | Downstream signaling molecule |
| PTPN11 | Encodes SHP-2 phosphatase | Potential mediator of AT2R effects |
| MAPK1 | Encodes ERK2, a kinase regulated by AT2R | Involved in proliferation/apoptosis decisions |
| MAPK3 | Encodes ERK1 | Involved in AT2R signaling |
| AKT1 | Encodes Akt1, a survival kinase | Modulated by AT2R signaling |
How Is type 2 angiotensin receptor binding Regulated?
The binding function of AT2R is regulated at multiple levels. Receptor expression can be influenced by transcriptional factors and by disease states such as hypertension [2,3]. Ligand availability is controlled by the renin-angiotensin system enzymes, including renin, ACE, and ACE2. At the protein level, AT2R can be phosphorylated and desensitized by β-arrestins, which affect its binding and signaling. Heterodimerization with AT1R can also modulate AT2R binding properties. Additionally, Gi protein coupling is essential for downstream signaling following binding.
type 2 angiotensin receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| AGTR2 | Hypertension, cardiovascular disease | Agtr2 knockout mouse, overexpression in cardiomyocytes [1,3] |
| AGT | Hypertension | Agt transgenic or knockout models |
| ACE2 | Cardiovascular and renal disease | Ace2 knockout or overexpression |
| AGTR1 | Hypertension, cardiac hypertrophy | Agtr1 knockout, heterodimerization studies |
| NOS3 | Endothelial dysfunction | Nos3 knockout, AT2R agonist treatment |
Hypertension and cardiovascular disease
AT2R binding and signaling are implicated in blood pressure regulation. Angiotensin-(1-9), a ligand for AT2R, has been studied in hypertension, and AT2R activation can promote vasodilation, counteracting AT1R-mediated vasoconstriction. Dysregulation of this balance can contribute to hypertension and cardiovascular remodeling.
Renal disease
AT2R is expressed in the adult kidney, where it promotes cellular proliferation and apoptosis. This suggests a role in renal injury and repair. Modulation of AT2R binding may affect the progression of kidney diseases.
Cardiac remodeling and heart failure
AT2R signaling can influence cardiac hypertrophy and fibrosis. Studies have shown that AT2R activation can have protective effects in heart failure models, partly through vasodilation and antiproliferative actions [1,3].
From type 2 angiotensin receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does AT2R binding mediate vasodilation? | Agtr2 knockout mouse with blood pressure telemetry |
| What is the role of AT2R in renal proliferation? | Agtr2 knockout or overexpression in kidney cells |
| How does AT2R heterodimerization affect signaling? | Knock-in of tagged AT2R and AT1R in cell lines |
| Which ligands selectively bind AT2R? | Point mutations in AT2R binding pocket |
| Can AT2R activation protect against heart failure? | Cardiac-specific AT2R overexpression in mouse models |
| What are downstream effectors of AT2R? | CRISPR knockout of candidate genes (e.g., GNAI1) followed by AT2R stimulation |
How to Study the type 2 angiotensin receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding | Ligand-receptor affinity and kinetics | Characterizing AT2R binding properties |
| CRISPR knockout | Loss of receptor function | Validating AT2R-specific effects |
| cAMP assay | Gi-mediated inhibition of adenylyl cyclase | Measuring AT2R activation |
| Apoptosis assay | Cell death induction | Assessing AT2R pro-apoptotic effects |
| Western blot | Protein expression and phosphorylation | Detecting downstream signaling |
| Immunofluorescence | Receptor localization | Visualizing AT2R trafficking |
| Nitric oxide measurement | Vasodilation mediator | Linking AT2R to endothelial function |
| Heterodimerization assay | Protein-protein interaction | Studying AT2R-AT1R complexes |
Radioligand binding assays
Radioligand binding assays using 125I-angiotensin II are standard for measuring AT2R binding affinity and kinetics. These assays can be performed on membrane preparations from cells or tissues expressing AT2R [1,7].
CRISPR-based gene editing
CRISPR/Cas9 can be used to generate AGTR2 knockout cells or animals to study the loss of binding function. Knock-in of point mutations in the AT2R binding pocket can reveal residues critical for ligand interaction [3,7].
Signal transduction assays
Downstream signaling can be measured by assessing Gi activation (e.g., cAMP inhibition), nitric oxide production, or apoptosis markers following AT2R stimulation [1,6,8].
Imaging and localization
Fluorescently tagged AT2R or ligand can be used to visualize binding and internalization in live cells. This helps confirm receptor localization and trafficking.
How CRISPR Can Be Used to Study GO:0031703 type 2 angiotensin receptor binding
Knockout
CRISPR knockout of AGTR2 eliminates AT2R binding and signaling, providing a clean background to test the specific contribution of this receptor to cellular responses. Such models are valuable for validating ligand specificity and downstream effects.
Point Mutation
Introducing point mutations in the AT2R binding pocket can identify residues critical for ligand binding. This approach helps dissect the molecular determinants of binding affinity and selectivity.
Knock-in
Knock-in of tagged AT2R (e.g., FLAG or GFP) allows for affinity purification and imaging of the receptor in its native context. This can reveal binding dynamics and interacting proteins.
Overexpression
Overexpression of AT2R in cell lines or transgenic animals can amplify binding signals and downstream effects, facilitating biochemical and physiological studies [1,3].
How EDITGENE Supports type 2 angiotensin receptor binding Research
Researchers studying type 2 angiotensin receptor binding-related genes often need to determine whether a candidate gene is causally involved in AT2R function or whether it merely correlates with observed phenotypes. CRISPR-based models provide a rigorous way to establish causality.
Contact EDITGENE today to design your custom CRISPR model for type 2 angiotensin receptor binding research.
Frequently Asked Questions About type 2 angiotensin receptor binding
What is type 2 angiotensin receptor binding?
It is the molecular function defined by GO:0031703, describing the binding of a ligand to the angiotensin II type 2 receptor (AT2R).
What genes are involved in type 2 angiotensin receptor binding?
The primary gene is AGTR2, which encodes the AT2R. Other related genes include AGT, REN, ACE, and ACE2, which produce ligands [2,3].
What is the function of AT2R?
AT2R mediates vasodilation, inhibits cell proliferation, and promotes apoptosis, often counteracting AT1R effects [1,6,8].
Which diseases are associated with AT2R binding?
Hypertension, cardiovascular disease, and renal disease have been linked to AT2R function [2,3,8].
How can I study AT2R binding in the lab?
Common methods include radioligand binding assays, CRISPR knockout, and downstream signaling assays [1,3,6].
What are the endogenous ligands for AT2R?
Angiotensin II and angiotensin-(1-9) are known ligands for AT2R [2,7].
Does AT2R couple to Gi proteins?
Yes, AT2R can activate Gi proteins, leading to inhibition of adenylyl cyclase.
What is the difference between AT1R and AT2R?
AT1R primarily couples to Gq and mediates vasoconstriction, while AT2R couples to Gi and promotes vasodilation and apoptosis [1,3].
Can CRISPR be used to study AT2R binding?
Yes, CRISPR knockout, knock-in, and point mutation models are powerful tools to dissect AT2R binding and signaling [3,7].
Where is AT2R expressed?
AT2R is expressed in adult kidney, cardiovascular tissues, and other organs [3,8].
Conclusion
Type 2 angiotensin receptor binding (GO:0031703) is a fundamental molecular function in the renin-angiotensin system, with critical roles in cardiovascular and renal physiology. Understanding the binding mechanism and its regulation can provide insights into disease pathogenesis and guide therapeutic development. CRISPR-based models offer robust tools to study this function in health and disease.
References
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- 3. Chow BS et al.. 2016. Angiotensin II type 2 receptor (AT2R) in renal and cardiovascular disease.. Clin Sci (Lond) 130(15):1307-26 PMID: 27358027
- 4. Tóth AD et al.. 2017. Angiotensin type 1A receptor regulates β-arrestin binding of the β(2)-adrenergic receptor via heterodimerization.. Mol Cell Endocrinol 442:113-124 PMID: 27908837
- 5. Duarte DA et al.. 2022. Angiotensin II Type 1 Receptor Tachyphylaxis Is Defined by Agonist Residence Time.. Hypertension 79(1):115-125 PMID: 34739768
- 6. Hansen JL et al.. 2000. Functional reconstitution of the angiotensin II type 2 receptor and G(i) activation.. Circ Res 87(9):753-9 PMID: 11055978
- 7. Wagenaar GTM et al.. 2023. Evolving views on the first two ligands of the angiotensin II type 2 receptor. From putative antagonists to potential agonists?. Eur J Pharmacol 961:176189 PMID: 37951489
- 8. Cao Z et al.. 2000. Angiotensin type 2 receptor is expressed in the adult rat kidney and promotes cellular proliferation and apoptosis.. Kidney Int 58(6):2437-51 PMID: 11115077
