Combinatorial expression of GPCR isoforms affects signalling and drug responses

Area of Science:

• Molecular Biology
• Pharmacology
• Genomics

Background:

• G-protein-coupled receptors (GPCRs) are crucial membrane proteins regulating physiological processes via extracellular signals.
• GPCR signaling is influenced by receptor sequence and expression, leading to variations across physiological systems.
• Functional diversity in GPCR isoforms, arising from differential tissue expression, is an underappreciated source of signaling bias.

Purpose of the Study:

• To investigate how a single GPCR gene diversifies into functionally distinct isoforms.
• To explore how unique combinations of GPCR isoforms expressed in different tissues generate distinct signaling states.
• To identify how structural changes and expression patterns of GPCR isoforms influence drug responses and therapeutic targeting.

Main Methods:

• Integration of human tissue transcriptomes, GPCR sequences and structures, proteomics, and single-cell transcriptomics.
• Analysis of population-wide genetic association studies and pharmacological experiments.
• Comparative analysis of GPCR isoform expression and signaling properties across diverse human tissues.

Main Results:

• Demonstrated that a single GPCR gene can produce multiple isoforms with distinct signaling capabilities.
• Showcased how specific isoform combinations in different tissues establish unique signaling states.
• Identified GPCR isoforms whose structural variations and expression patterns may affect drug efficacy and selectivity.

Conclusions:

• GPCR signaling is context-dependent, influenced by the combinatorial expression of isoforms within specific cell types and tissues.
• Understanding tissue-specific GPCR isoform expression is essential for a nuanced view of receptor signaling.
• GPCR isoforms represent potential targets for developing drugs with enhanced tissue selectivity and improved therapeutic outcomes.