Development of a red fluorescent protein-based cGMP indicator applicable for live-cell imaging

Cyclic guanosine 3 ', 5 '-monophosphate (cGMP) is a second messenger that regulates a variety of physiological processes. Here, we develop a red fluorescent protein-based cGMP indicator, Red cGull. The fluorescence intensity of Red cGull increase more than sixfold in response to cGMP. The features of this indicator include an EC50 of 0.33 mu M for cGMP, an excitation and emission peak at 567 nm and 591 nm, respectively. Live-cell imaging analysis reveal the utility of Red cGull for dual-colour imaging and its ability to be used in conjunction with optogenetics tools. Using enteroendocrine cell lines, Red cGull detects an increase in cGMP following the application of l-arginine. An increase in intracellular cGMP is found to be inhibited by Ca2+, and l-arginine-mediated hormone secretion is not potentiated. We propose that Red cGull will facilitate future research in cell signalling in relation to cGMP and its interplay with other signalling molecules. A red fluorescent protein-based indicator of cyclic guanosine 3 ', 5 '-monophosphate (cGMP) allows for multi-colour imaging and optogenetic applications while monitoring cGMP activity in cells.

Automated summary

A red fluorescent protein-based indicator, Red cGull, allows for multi-colour imaging and optogenetic applications while monitoring cGMP activity in cells.