cAMP Biosensors Based on Genetically Encoded Fluorescent/Luminescent Proteins

Abstract

Cyclic adenosine monophosphate (cAMP) plays a key role in signal transduction pathways as a second messenger. Studies on the cAMP dynamics provided useful scientific insights for drug development and treatment of cAMP-related diseases such as some cancers and prefrontal cortex disorders. For example, modulation of cAMP-mediated intracellular signaling pathways by anti-tumor drugs could reduce tumor growth. However, most early stage tools used for measuring the cAMP level in living organisms require cell disruption, which is not appropriate for live cell imaging or animal imaging. Thus, in the last decades, tools were developed for real-time monitoring of cAMP distribution or signaling dynamics in a non-invasive manner. Genetically-encoded sensors based on fluorescent proteins and luciferases could be powerful tools to overcome these drawbacks. In this review, we discuss the recent genetically-encoded cAMP sensors advances, based on single fluorescent protein (FP), Föster resonance energy transfer (FRET), single luciferase, and bioluminescence resonance energy transfer (BRET) for real-time non-invasive imaging.

cAMP Compartmentalization in Cerebrovascular Endothelial Cells: New Therapeutic Opportunities in Alzheimer’s Disease

“…In addition to FRET, other approaches were used in recent years to measure localized variations in cAMP concentrations, including fluorescent proteins that modify their fluorescence intensity based on their binding to cAMP, single luciferase-based cAMP sensors, or bioluminescence resonance energy transfer (BRET)-based cAMP sensors [80]. Moreover, new probes have been designed that can detect variations in the concentration of cAMP at a micro or even nanoscale.…”

“…The main problem with some of these sensors may be due to a different physiological behaviors or to the different affinities that they may have for cAMP in relation to the unlabeled molecule, which sometimes makes the interpretation of the results difficult. For recent and detailed reviews of cAMP measurement techniques, see, for example, Zaccolo et al [73], Kim et al [80], Ghigo and Mika [81], Judina et al [82], or Chao et al [83].…”

Chemical-Biology-derived in vivo Sensors: Past, Present, and Future

“…[8] Ca 2+ sensing is reviewed extensively in the literature and not discussed further here; rather it serves as a high-water mark for what biosensors can achieve. Indeed, the remarkable successes in sensing Ca 2+ inspired the creation of sensors of chloride, [9] Cu + [10] as well as important metabolites such as cAMP [11] and nicotinamide adenine dinucleotides. [12] Other analyte sensors are sure to follow.…”

Time-Domain Fluorescence Lifetime Imaging of cAMP Levels with EPAC-Based FRET Sensors

“…Several groups reported on EPAC-based cAMP FRET sensors [16]. Nikolaev et al [14] made a compact FRET sensor by fusing the cyclic nucleotide binding domains of EPAC1 and EPAC2 in-between donor and acceptor fluorophores.…”