GO:0017098 sulfonylurea receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0017098 sulfonylurea receptor binding is a molecular function defined as binding to a sulfonylurea receptor, a regulatory subunit of the ATP-sensitive potassium ion channel.
• The sulfonylurea receptor (SUR) is an atypical ATP-binding cassette (ABC) protein that regulates KATP channel activity.
• Sulfonylurea drugs, used to treat type 2 diabetes, act by binding to SUR and closing KATP channels, thereby stimulating insulin secretion.
• SUR1 and SUR2 are the major isoforms, encoded by ABCC8 and ABCC9, respectively, and are differentially expressed in pancreatic beta cells, heart, and smooth muscle.
• Mutations in ABCC8 and ABCC9 cause neonatal diabetes, congenital hyperinsulinism, and cardiac and vascular disorders.
• Research on sulfonylurea receptor binding uses knockout, knock-in, and point-mutation cell models, often combined with electrophysiology and ligand-binding assays.
Description
Sulfonylurea receptor binding (GO:0017098) is a molecular function that describes the interaction of a ligand with a sulfonylurea receptor, which is a regulatory subunit of the ATP-sensitive potassium (KATP) channel. This binding event is central to the mechanism of action of sulfonylurea drugs, a class of compounds widely used to treat type 2 diabetes by stimulating insulin secretion from pancreatic beta cells. The sulfonylurea receptor (SUR) is an atypical ATP-binding cassette (ABC) protein that does not transport substrates but instead regulates channel gating in response to nucleotides and pharmacological agents. Because of its critical role in glucose homeostasis and its involvement in various diseases, sulfonylurea receptor binding is a key area of biomedical research. Understanding this function at the molecular level can inform drug design and the development of precision therapies for conditions such as neonatal diabetes and congenital hyperinsulinism.
sulfonylurea receptor binding At A Glance
| GO ID | GO:0017098 |
|---|---|
| GO term | sulfonylurea receptor binding |
| Ontology | molecular_function |
| Synonym | sulfonylurea receptor ligand, sulphonylurea receptor binding |
| Major function | Binding to a sulfonylurea receptor, a regulatory subunit of the ATP-sensitive potassium ion channel |
| Related genes | ABCC8 (SUR1), ABCC9 (SUR2), KCNJ8 (Kir6.1), KCNJ11 (Kir6.2) |
| Associated diseases | Neonatal diabetes, congenital hyperinsulinism, cardiac arrhythmias, cerebral edema |
| Research methods | Electrophysiology, ligand-binding assays, CRISPR knockout/knock-in models |
What Is GO:0017098?
According to the Gene Ontology, GO:0017098 sulfonylurea receptor binding is defined as the binding to a sulfonylurea receptor, a regulatory subunit of the ATP-sensitive potassium ion channel. In other words, it is the molecular function of a ligand (such as a sulfonylurea drug or an endogenous molecule) physically interacting with the sulfonylurea receptor protein, which modulates the activity of the KATP channel.
Why Is sulfonylurea receptor binding Important in Cell Biology?
Sulfonylurea receptor binding is important because it is the molecular basis for the therapeutic action of sulfonylurea drugs, which are among the most prescribed oral antidiabetic agents worldwide. Beyond pharmacology, this binding function is critical for understanding how KATP channels are regulated in response to metabolic signals, and how mutations in the sulfonylurea receptor lead to diseases such as neonatal diabetes and congenital hyperinsulinism. Moreover, the sulfonylurea receptor is implicated in neuroprotection and cardiovascular function, making it a target for drug discovery beyond diabetes.
• Sulfonylurea receptor binding mediates the insulin-secretagogue effect of sulfonylurea drugs in type 2 diabetes.
• Mutations in ABCC8 (SUR1) that alter sulfonylurea binding cause neonatal diabetes and congenital hyperinsulinism.
• The sulfonylurea receptor is a key regulator of KATP channel activity in pancreatic beta cells, heart, and smooth muscle.
• Sulfonylurea receptor binding is studied to develop new drugs for diabetes and other metabolic disorders.
• In the central nervous system, sulfonylurea receptor 1 (SUR1) is involved in cerebral edema and neuroinflammation after injury.
• Cardiac KATP channels, regulated by SUR2A, are important in ischemic preconditioning and arrhythmia.
• Understanding sulfonylurea receptor binding can guide personalized medicine for patients with ABCC8/ABCC9 mutations.
• The binding function is a model for studying atypical ABC proteins that regulate ion channels.
• Research on sulfonylurea receptor binding uses advanced techniques like cryo-EM and electrophysiology.
• Targeting sulfonylurea receptor binding may have therapeutic potential in stroke and traumatic brain injury.
Molecular Mechanism of sulfonylurea receptor binding
Ligand recognition and binding site
In simple terms: The sulfonylurea drug fits into a specific pocket on the sulfonylurea receptor protein.
The sulfonylurea receptor (SUR) contains a binding site for sulfonylurea ligands, which are typically small molecules with a sulfonylurea moiety. This site is located within the transmembrane domains of SUR, and binding is thought to involve both the transmembrane helices and the nucleotide-binding domains (NBDs). The exact residues involved in sulfonylurea binding have been studied using photoaffinity labeling and mutagenesis, revealing that the binding pocket is distinct from the ATP-binding site.
Conformational changes upon binding
In simple terms: When the drug binds, the receptor changes shape, which closes the potassium channel.
Binding of sulfonylureas to SUR induces conformational changes that are transmitted to the pore-forming Kir6.x subunits, leading to channel closure. Recent studies using ATP binding without hydrolysis have shown that SUR1 can switch to outward-facing conformations that activate KATP channels, and sulfonylureas stabilize an inward-facing conformation that inhibits channel activity. This allosteric mechanism is central to the pharmacological action of sulfonylureas.
Role of nucleotides and Mg-ATP
In simple terms: ATP and other nucleotides can also bind to the receptor and affect how well sulfonylureas work.
The sulfonylurea receptor is an ABC protein with nucleotide-binding domains that bind ATP and ADP. Nucleotide binding modulates the affinity of SUR for sulfonylureas and influences channel gating. For example, Mg-ATP binding to SUR1 can increase the potency of sulfonylureas in closing KATP channels, while Mg-ADP can antagonize this effect. This interplay between nucleotides and sulfonylureas is critical for the physiological regulation of insulin secretion.
Coupling to KATP channel gating
In simple terms: The receptor and the channel are physically connected, so binding at the receptor directly controls the channel gate.
SUR is tightly associated with the Kir6.x subunits, forming a functional octameric complex. Binding of sulfonylureas to SUR causes a conformational change that is transmitted through the interface between SUR and Kir6.x, resulting in pore closure. This coupling is essential for the inhibitory effect of sulfonylureas on KATP channel activity, which leads to membrane depolarization and insulin secretion in beta cells.
Pharmacological specificity and isoform differences
In simple terms: Different types of sulfonylurea receptors (SUR1, SUR2A, SUR2B) respond differently to drugs, which affects their use in different tissues.
SUR1, SUR2A, and SUR2B exhibit distinct pharmacological profiles for sulfonylureas and other KATP channel openers and blockers. For instance, SUR1 is highly sensitive to glibenclamide, while SUR2A is less sensitive. These differences are exploited in drug design to target specific tissues, such as pancreatic beta cells versus cardiac muscle. Understanding isoform-specific binding is crucial for developing selective therapeutics.
Key Genes Involved in GO:0017098 sulfonylurea receptor binding
The following genes encode proteins that are directly involved in sulfonylurea receptor binding or that form the KATP channel complex.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ABCC8 | Encodes SUR1, the high-affinity sulfonylurea receptor in pancreatic beta cells and neurons | Mutations cause neonatal diabetes and congenital hyperinsulinism; target for diabetes drugs |
| ABCC9 | Encodes SUR2A and SUR2B, receptors in cardiac and smooth muscle | Mutations linked to cardiac arrhythmias and vascular disorders; drug target for cardiovascular diseases |
| KCNJ11 | Encodes Kir6.2, the pore-forming subunit of KATP channels in beta cells and neurons | Mutations cause neonatal diabetes; interacts with SUR1 to form functional channels |
| KCNJ8 | Encodes Kir6.1, the pore-forming subunit in smooth muscle and heart | Forms channels with SUR2B; involved in vascular tone regulation |
| NBD1 | Nucleotide-binding domain 1 of SUR (part of ABCC8/ABCC9) | Binds ATP and modulates sulfonylurea binding affinity |
| NBD2 | Nucleotide-binding domain 2 of SUR | Binds Mg-ATP and regulates channel gating; site of disease mutations |
| TMD0 | Transmembrane domain 0 of SUR | Involved in channel coupling and possibly sulfonylurea binding |
| TMD1 | Transmembrane domain 1 of SUR | Contains part of the sulfonylurea binding pocket |
| TMD2 | Transmembrane domain 2 of SUR | Contains part of the sulfonylurea binding pocket |
| SUR1 | Sulfonylurea receptor 1 protein (encoded by ABCC8) | Primary target of sulfonylurea drugs in beta cells; studied in diabetes and neuroprotection |
| SUR2A | Sulfonylurea receptor 2A protein (encoded by ABCC9) | Cardiac KATP channel regulator; target for cardiac ischemia |
| SUR2B | Sulfonylurea receptor 2B protein (encoded by ABCC9) | Smooth muscle KATP channel regulator; involved in vascular tone |
| Kir6.2 | Inwardly rectifying potassium channel subunit (encoded by KCNJ11) | Pore-forming subunit; mutations cause neonatal diabetes |
| Kir6.1 | Inwardly rectifying potassium channel subunit (encoded by KCNJ8) | Pore-forming subunit in smooth muscle; regulates vascular function |
| Glibenclamide | Second-generation sulfonylurea drug | High-affinity ligand for SUR1; used to study binding and channel closure |
| Gliclazide | Sulfonylurea drug | Used in type 2 diabetes; binds SUR1 with lower affinity than glibenclamide |
| Tolbutamide | First-generation sulfonylurea drug | Prototype ligand for studying SUR binding |
| Diazoxide | KATP channel opener | Binds SUR and activates channel; used to treat hyperinsulinism |
How Is sulfonylurea receptor binding Regulated?
Sulfonylurea receptor binding is regulated by intracellular nucleotides, particularly ATP and ADP, which bind to the nucleotide-binding domains of SUR and modulate its affinity for sulfonylureas. Additionally, phosphorylation by protein kinases and interaction with other proteins can influence receptor function. The expression levels of SUR isoforms are also regulated in a tissue-specific manner, affecting the overall binding capacity.
sulfonylurea receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ABCC8 | Neonatal diabetes, congenital hyperinsulinism | Knockout mice, patient-derived iPSCs, point-mutation knock-in |
| ABCC9 | Cardiac arrhythmia, dilated cardiomyopathy | Cardiac-specific knockout, knock-in mice, hiPSC-derived cardiomyocytes |
| KCNJ11 | Neonatal diabetes, developmental delay | Knock-in mice, CRISPR point mutation in cell lines |
| SUR1 | Cerebral edema after stroke | Middle cerebral artery occlusion in rats, SUR1 knockout mice |
| SUR2A | Ischemic preconditioning | Cardiac-specific overexpression, knockout mice |
Neonatal diabetes and congenital hyperinsulinism
Mutations in ABCC8 (SUR1) that impair or enhance sulfonylurea receptor binding can cause neonatal diabetes or congenital hyperinsulinism, respectively. In neonatal diabetes, mutations often reduce channel inhibition by ATP, leading to excessive insulin secretion, while in hyperinsulinism, mutations cause channel overactivity and reduced insulin secretion. Sulfonylurea drugs are used to treat neonatal diabetes by binding to mutant SUR1 and closing the channel.
Cardiovascular disorders
ABCC9 (SUR2) mutations are associated with cardiac arrhythmias, dilated cardiomyopathy, and vascular abnormalities. Sulfonylurea receptor binding in cardiac KATP channels is important for ischemic preconditioning, and drugs that modulate this binding are being explored for cardioprotection.
Central nervous system injury
SUR1 is upregulated in the brain after ischemic stroke and traumatic brain injury, where it contributes to cerebral edema and neuronal death. Sulfonylurea receptor binding by glibenclamide has been shown to reduce edema and improve outcomes in preclinical models, making it a potential therapeutic target for CNS injury.
From sulfonylurea receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SUR1 affect insulin secretion? | ABCC8 knockout pancreatic beta cell line (e.g., INS-1) or mouse islets |
| How does a specific point mutation in ABCC8 alter sulfonylurea binding? | CRISPR point-mutation knock-in in HEK293 or INS-1 cells |
| Can a tagged SUR1 be used to study binding dynamics? | Knock-in of fluorescent tag (e.g., GFP) at ABCC8 locus |
| Does overexpression of SUR2A protect against cardiac ischemia? | Transgenic mouse with cardiac-specific SUR2A overexpression |
| What is the effect of a patient-derived ABCC8 mutation? | Patient iPSC-derived beta cells with CRISPR correction |
| Can CRISPR library screening identify modifiers of sulfonylurea sensitivity? | Genome-wide CRISPR knockout library in beta cell line |
How to Study the sulfonylurea receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch-clamp electrophysiology | KATP channel activity | Functional effect of sulfonylureas on channel closure |
| Radioligand binding | Binding affinity (Kd) and Bmax | Quantify sulfonylurea binding to SUR |
| CRISPR knockout | Loss of gene function | Determine if SUR is required for drug response |
| CRISPR knock-in | Introduction of specific mutations | Model patient mutations in cell lines |
| Western blot | Protein expression levels | Assess SUR expression after genetic manipulation |
| Immunofluorescence | Subcellular localization | Visualize SUR trafficking and localization |
| RNA-seq | Transcriptional changes | Identify genes regulated by sulfonylurea treatment |
Electrophysiology
Patch-clamp recordings measure KATP channel activity in response to sulfonylureas, providing direct functional readout of sulfonylurea receptor binding. This method is used to assess the effect of mutations on channel inhibition by drugs.
Ligand-binding assays
Radioligand binding assays using tritiated glibenclamide or other sulfonylureas quantify binding affinity and kinetics to SUR in membrane preparations or intact cells. These assays are essential for determining the pharmacological profile of novel compounds.
CRISPR-based genome editing
CRISPR/Cas9 knockout, knock-in, and point-mutation models allow researchers to dissect the role of specific residues in sulfonylurea binding and to create disease-relevant mutations. These models are used in combination with functional assays to link genotype to phenotype.
Structural biology
Cryo-electron microscopy and X-ray crystallography have provided structures of SUR in complex with sulfonylureas, revealing the binding pocket and conformational changes. These structural insights guide drug design.
How CRISPR Can Be Used to Study GO:0017098 sulfonylurea receptor binding
Knockout
CRISPR knockout of ABCC8 or ABCC9 eliminates sulfonylurea receptor expression, allowing researchers to study the loss of binding and its downstream effects on KATP channel activity and insulin secretion. These models are valuable for validating drug targets and understanding disease mechanisms.
Point Mutation
CRISPR point mutation introduces specific disease-associated mutations (e.g., in ABCC8) to study how single amino acid changes alter sulfonylurea binding affinity and channel gating. This approach is crucial for personalized medicine and drug response prediction.
Knock-in
Knock-in of reporter tags (e.g., GFP) or patient mutations into the endogenous ABCC8 locus enables real-time tracking of SUR expression and localization, and provides physiologically relevant models for drug testing.
Overexpression
Overexpression of SUR1 or SUR2 in cell lines (e.g., HEK293, INS-1) using CRISPR activation or lentiviral vectors increases binding capacity, facilitating biochemical and structural studies of sulfonylurea receptor binding.
How EDITGENE Supports sulfonylurea receptor binding Research
Researchers studying sulfonylurea receptor binding-related genes often need to determine whether a candidate gene is causally involved in drug response or disease. EDITGENE provides comprehensive CRISPR-based services to create precise cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for sulfonylurea receptor binding research.
Frequently Asked Questions About sulfonylurea receptor binding
What is sulfonylurea receptor binding?
Sulfonylurea receptor binding (GO:0017098) is the molecular function of a ligand binding to a sulfonylurea receptor, a regulatory subunit of the ATP-sensitive potassium channel.
What genes are involved in sulfonylurea receptor binding?
The main genes are ABCC8 (encoding SUR1) and ABCC9 (encoding SUR2A/SUR2B), which form the regulatory subunits of KATP channels.
What diseases are associated with sulfonylurea receptor binding?
Mutations in ABCC8 and ABCC9 cause neonatal diabetes, congenital hyperinsulinism, cardiac arrhythmias, and are implicated in cerebral edema after stroke.
How do sulfonylurea drugs work?
Sulfonylurea drugs bind to the sulfonylurea receptor, causing KATP channel closure, membrane depolarization, and insulin secretion in pancreatic beta cells.
What is the role of SUR1 in the brain?
SUR1 is upregulated after brain injury and contributes to cerebral edema; blocking sulfonylurea receptor binding with glibenclamide reduces edema in preclinical models.
What research methods are used to study sulfonylurea receptor binding?
Common methods include patch-clamp electrophysiology, radioligand binding assays, CRISPR knockout/knock-in models, and structural biology techniques like cryo-EM.
Can CRISPR be used to study sulfonylurea receptor binding?
Yes, CRISPR knockout, point mutation, and knock-in models allow precise manipulation of ABCC8 and ABCC9 to study binding and channel function.
What are the isoforms of the sulfonylurea receptor?
The main isoforms are SUR1 (ABCC8), SUR2A, and SUR2B (both ABCC9), which differ in tissue distribution and pharmacological properties.
How does ATP affect sulfonylurea receptor binding?
ATP binds to the nucleotide-binding domains of SUR and modulates its affinity for sulfonylureas, influencing channel gating.
What cell models are available for sulfonylurea receptor research?
EDITGENE provides knockout, point-mutation, knock-in, and overexpression cell models for ABCC8, ABCC9, and related genes, as well as CRISPR library screening services.
Conclusion
Sulfonylurea receptor binding (GO:0017098) is a fundamental molecular function that underlies the pharmacology of sulfonylurea drugs and the physiological regulation of KATP channels. Its importance extends from diabetes to cardiovascular and neurological disorders, making it a vibrant area of research. By leveraging CRISPR-based cell models and advanced assays, researchers can dissect the molecular details of this binding event and develop new therapeutic strategies.
References
- 1. Burke MA et al.. 2008. The sulfonylurea receptor, an atypical ATP-binding cassette protein, and its regulation of the KATP channel.. Circ Res 102(2):164-76 PMID: 18239147
- 2. Boyd AE 3rd et al.. 1991. Sulfonylurea signal transduction.. Recent Prog Horm Res 47:299-316; discussion 316-7 PMID: 1660613
- 3. Ashcroft SJ et al.. 1992. The sulfonylurea receptor.. Biochim Biophys Acta 1175(1):45-59 PMID: 1482696
- 4. Sikimic J et al.. 2019. ATP binding without hydrolysis switches sulfonylurea receptor 1 (SUR1) to outward-facing conformations that activate K(ATP) channels.. J Biol Chem 294(10):3707-3719 PMID: 30587573
- 5. Jha RM et al.. 2021. Sulfonylurea Receptor 1 in Central Nervous System Injury: An Updated Review.. Int J Mol Sci 22(21) PMID: 34769328
- 8. Backx PH. 2008. Sulfonylurea receptor expression heterogeneity suggests chamber-specific roles for sarcolemmal KATP channels in heart.. Circ Res 103(12):1345-7 PMID: 19059835
