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A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators
Published on: February 20, 2018
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A cryptic mode of GPCR regulation revealed
Deepak A Deshpande1, Raymond B Penn1
1Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Respiratory Institute, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Trends in Molecular Medicine
|September 15, 2022
Summary
Researchers discovered that S-nitrosylation of the beta-2 adrenoceptor (β2AR) is crucial for its desensitization and internalization. This finding reveals a new mechanism regulating G protein-coupled receptor (GPCR) signaling and offers potential therapeutic targets.
Area of Science:
- G protein-coupled receptor (GPCR) research
- Cellular signaling mechanisms
- Respiratory disease pathways
Background:
- G protein-coupled receptors (GPCRs) are key regulators of cellular processes.
- Decades of research have elucidated many GPCR regulation mechanisms.
- A novel desensitization pathway for the beta-2 adrenoceptor (β2AR) has been identified.
Purpose of the Study:
- To identify previously overlooked mechanisms of GPCR regulation.
- To investigate the role of S-nitrosylation in β2AR desensitization.
- To explore the functional consequences of altered β2AR S-nitrosylation.
Main Methods:
- Agonist activation of β2AR.
- Site-directed mutagenesis (C265 mutation) to prevent S-nitrosylation.
- Assessment of receptor internalization and desensitization.
- Measurement of protein kinase A (PKA) and nitric oxide (NO) signaling.
- In vivo studies in mice, including resistance to bronchoconstriction and protection from allergen-induced asthma.
Main Results:
- Agonist stimulation triggers β2AR S-nitrosylation, essential for internalization and desensitization.
- Mutation of C265 abolished β2AR S-nitrosylation, leading to enhanced PKA signaling.
- Loss of S-nitrosylation enabled β2AR nitric oxide (NO) signaling.
- Mice lacking β2AR S-nitrosylation exhibited resistance to bronchoconstriction and protection from asthma.
Conclusions:
- β2AR S-nitrosylation is a critical, previously unrecognized mechanism for receptor desensitization.
- This S-nitrosylation event regulates both PKA and NO signaling pathways.
- Targeting β2AR S-nitrosylation may offer new therapeutic strategies for asthma and bronchoconstriction.
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