[HTML][HTML] Fourth-generation epac-based FRET sensors for cAMP feature exceptional brightness, photostability and dynamic range: characterization of dedicated …

J Klarenbeek, J Goedhart, A Van Batenburg… - PloS one, 2015 - journals.plos.org
J Klarenbeek, J Goedhart, A Van Batenburg, D Groenewald, K Jalink
PloS one, 2015journals.plos.org
Epac-based FRET sensors have been widely used for the detection of cAMP concentrations
in living cells. Originally developed by us as well as others, we have since then reported
several important optimizations that make these sensors favourite among many cell
biologists. We here report cloning and characterization of our fourth generation of cAMP
sensors, which feature outstanding photostability, dynamic range and signal-to-noise ratio.
The design is based on mTurquoise2, currently the brightest and most bleaching-resistant …
Epac-based FRET sensors have been widely used for the detection of cAMP concentrations in living cells. Originally developed by us as well as others, we have since then reported several important optimizations that make these sensors favourite among many cell biologists. We here report cloning and characterization of our fourth generation of cAMP sensors, which feature outstanding photostability, dynamic range and signal-to-noise ratio. The design is based on mTurquoise2, currently the brightest and most bleaching-resistant donor, and a new acceptor cassette that consists of a tandem of two cp173Venus fluorophores. We also report variants with a single point mutation, Q270E, in the Epac moiety, which decreases the dissociation constant of cAMP from 9.5 to 4 μM, and thus increases the affinity ~ 2.5-fold. Finally, we also prepared and characterized dedicated variants with non-emitting (dark) acceptors for single-wavelength FLIM acquisition that display an exceptional near-doubling of fluorescence lifetime upon saturation of cAMP levels. We believe this generation of cAMP outperforms all other sensors and therefore recommend these sensors for all future studies.
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