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Activation of Multiple G Protein Pathways to Characterize the Five Dopamine Receptor Subtypes Using Bioluminescence
Denise Mönnich1, Laura J Humphrys1, Carina Höring1
1Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
ACS Pharmacology & Translational Science
|March 14, 2024
Summary
Dopamine receptors can activate various G proteins, influencing drug design. Understanding this functional selectivity offers new therapeutic options for precise physiological event induction.
Area of Science:
- Pharmacology
- Neuroscience
- Biochemistry
Background:
- G protein-coupled receptors (GPCRs) exhibit G protein subtype preference, but can recruit multiple subtypes, leading to diverse downstream signaling.
- Dopamine receptors, crucial in the central nervous system, are classified as stimulatory (D1-like) and inhibitory (D2-like).
- Functional selectivity in G protein subunit recruitment by dopamine receptors presents opportunities for targeted drug design.
Purpose of the Study:
- To characterize G protein coupling and functional outcomes for all five dopamine receptors.
- To investigate the potential for Gq coupling and alternative signaling pathways.
- To assess the G protein selectivity of specific dopamine receptor agonists.
Main Methods:
- Utilized three bioluminescence-based assays: miniG protein assay (split luciferase) for recruitment, G-CASE BRET assay for activation and selectivity, and CAMYEN BRET assay for cAMP changes.
- Characterized dopamine receptor agonists and antagonists for their G protein recruitment and downstream cyclic adenosine monophosphate (cAMP) signaling effects.
- Investigated G protein coupling profiles across the five dopamine receptor subtypes.
Main Results:
- Dopamine receptors demonstrated potential Gq coupling and could activate signaling pathways with effects opposite to their canonical roles.
- The D1-like receptor agonist (+)-SKF-81297 selectively activated Gs, while the D2-like receptor agonist pramipexole selectively activated Gi/o/z across all receptors.
- Significant variations in G protein coupling and activation were observed among the five dopamine receptors, correlating with downstream cAMP signaling.
Conclusions:
- The five dopamine receptors exhibit diverse G protein coupling potentials and downstream signaling activities.
- Targeting specific dopamine receptor-G protein interactions can be achieved through rational drug design.
- This understanding enhances the potential for developing highly selective pharmacological treatments to elicit desired physiological responses.
