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Published on: August 16, 2018
Constitutive receptor systems for drug discovery
G Chen1, C Jayawickreme, J Way
1Department of Receptor Biochemistry, Glaxo Wellcome Research and Development, 5 Moore Drive, Research Triangle Park, NC 27709, USA.
Constitutively active G-protein-coupled receptor systems offer advantages for drug discovery by detecting both agonists and antagonists. These systems show increased sensitivity, particularly for agonist detection, enhancing screening efficiency.
Area of Science:
- Pharmacology
- Molecular Biology
- Drug Discovery
Background:
- G-protein-coupled receptors (GPCRs) are crucial drug targets.
- Constitutive activity of GPCRs, or basal signaling without a ligand, is a known phenomenon.
- The ternary complex model provides a framework for understanding receptor-ligand interactions.
Purpose of the Study:
- To explore the utility of constitutively active GPCR systems in drug discovery.
- To evaluate the theoretical advantages of constitutive receptor screening.
- To experimentally validate the benefits of constitutive activity in receptor-ligand binding assays.
Main Methods:
- Utilized the ternary complex model to define theoretical advantages.
- Employed transient transfection of Chinese hamster ovary (CHO) cells with reporter genes (CRE luciferase).
- Expressed human parathyroid hormone (PTH-1), glucagon, glucagon-like peptide (GLP-1), and calcitonin receptors in cell systems.
- Assessed constitutive activity and ligand-induced responses in transfected cells and Xenopus laevis melanophores.
Main Results:
- Constitutive activity was observed for PTH-1 and glucagon receptors in CHO cells, dependent on cDNA concentration.
- GLP-1 receptor showed no constitutive activity, but responded to GLP-1, indicating successful expression.
- Human calcitonin receptor in Xenopus laevis melanophores exhibited constitutive activity, modulated by nine ligands.
- System sensitivity to human calcitonin increased with higher constitutive activity.
Conclusions:
- Constitutively active GPCR systems can be advantageous for drug discovery screening.
- These systems allow direct detection of both antagonists and agonists.
- Enhanced sensitivity to agonists is a key benefit of constitutive GPCR screening.
- The findings suggest that screening receptors with natural constitutive activity in this mode could outperform other methods.
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