Fluorescent sensors for rapid monitoring of intracellular cGMP

Sensors based on fluorescence resonance energy transfer (FRET) are powerful tools to monitor signaling events in living mammalian cells. Here we describe development and use of new sensors for cyclic GMP (cGMP) based on cGMP binding domains from cGMP-dependent protein kinase I (GKI) and from phosphodiesterases (PDEs). The temporal and spatial resolution attained with the new sensors is superior to that of existing techniques, and permits direct recording and imaging of rapid cGMP-signaling events.