Quantitative measurements of cAMP concentration with a new Epac based FRET-Sensor
FRET-based biosensors can be used for the analysis of intracellular signalling, including sensors for monitoring cyclic AMP. The concept is that the donor/acceptor emission ratio excited at the donor excitation wavelength can be used as a concentration dependent measure in donor/acceptor 1:1 tandem biosensors. General problem, however, is that this ratio varies not only with the changes in cAMP concentration, but also with the changes of the ionic environment or other factors affecting the folding probability. We are developing a novel Epac Based FRET-Sensor that is much less sensitive to changes in ion concentrations to obtain a reliable measure of the absolute cAMP concentrations under patho-/physiological conditions with high temporal and spatial resolution. Such data will be correlated with electrophysiological measurements obtained under pathological as well as physiological conditions.