The article provides information on a study conducted by N. Sudarsan and colleagues to determine how the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) is sensed by riboswitches. It mentions that the cellular effects of protein interactions that involve c-di-GMP could be explained by the presence of c-di-GMP riboswitches. It discusses that riboswitches are complex, structured RNA domains that act as receptors for specific metabolites.