Towards a Single-Molecule Pharmacology of G-Protein-Coupled Receptors: Understanding Receptor Dynamics to Develop Innovative Drugs

G-protein-coupled receptors (GPCRs) mediate the effects of several hormones and neurotransmitters and are major pharmacological targets. Despite recent advances, how GPCRs work in a cell to produce specific effects remains poorly understood. My group has developed an innovative single-molecule approach to investigate GPCRs in living cells with unprecedented spatiotemporal resolution. Using this approach, we recently succeeded for the first time in visualizing individual receptors and G-proteins as they interact and signal in living cells. We discovered that dynamic interactions among receptors, G-proteins and structural elements of the plasma membrane generate nanodomains where GPCRs produce highly localized signals (“hot spots”). We hypothesize that this organization is crucial for achieving efficient and specific signalling, its alterations might be implicated in diseases like heart failure, and might be exploited to modulate GPCR signalling beyond what is possible with current drugs. In this project, we will use beta-adrenergic receptors as a model and single-molecule microscopy to provide for the first time a detailed characterization of the key protein-protein and protein-lipid interaction involved in G-protein and beta-arrestin signalling, compare their nanoscale organization in cardiomyocytes under physiological and pathological conditions and, ultimately, exploit the new information to develop innovative therapeutic strategies for cardiovascular and metabolic diseases.