By limiting unrestricted activation of intracellular effectors, compartmentalised signalling of cyclic nucleotides confers specificity to extracellular stimuli and is critical for the development and health of cells and organisms. Dissecting the molecular mechanisms that allow local control of cyclic nucleotide signalling is essential for our understanding of physiology and pathophysiology but mapping the dynamics and regulation of compartmentalised signalling is a challenge. In this Minireview we summarise advanced imaging and proteomics techniques that have been successfully used to probe compartmentalised 3',5'-cyclic adenosine monophosphate (cAMP) signalling in eukaryotic cells. Subcellularly targeted fluorescence resonance energy transfer (FRET) sensors can precisely locate and measure compartmentalised cAMP, and this allows us to estimate the range of effector activation. As cAMP effector proteins often cluster together with their targets and cAMP regulatory proteins to form discrete cAMP signalosomes, proteomics and phosphoproteomics analysis have more recently been used to identify additional players in the cAMP signalling cascade. We propose that the synergistic use of the techniques discussed could prove fruitful in generating a detailed map of cAMP signalosomes and reveal new details of compartmentalised signalling. Compiling a dynamic map of cAMP nanodomains in defined cell types would establish a blueprint for better understanding the alteration of signalling compartments associated with disease and would provide a molecular basis for targeted therapeutic strategies. SIGNIFICANCE STATEMENT: cAMP signalling is compartmentalised. Some functionally important cellular signalling compartments operate on a nanometre scale, and their integrity is essential to maintain cellular function and appropriate responses to extracellular stimuli. Compartmentalised signalling provides an opportunity for precision medicine interventions. Our detailed understanding of the composition, function, and regulation of cAMP signalling nanodomains in health and disease is essential and will benefit from harnessing the right combination of advanced biochemical and imaging techniques.
Adenylyl cyclase, Adrenergic receptors, Phosphodiesterases, Protein Kinase A (PKA), cAMP