GEPII 1.0 untargeted

FRET (CFP/YFP) based genetically encoded potassium ion indicator w/o any targeting signal. Binding of K⁺ to the probe decreases the CFP fluorescence signal and increases FRET. The K_D of GEPII 1.0 is around 1 mM suitable for the detection of intracellular K⁺ fluctuations.

Reference: Bischof et al Nature Communications 2017