Cyclic-di-GMP is a naturally occurring small molecule that acts as a bacterial second messenger to regulate important signaling mechanisms in prokaryotes that control bacterial survival, adhesion, colonization, biofilm formation, and virulence factors production. During infections Cyclic-di-GMP is bound by host STING (stimulator of interferon genes) leading to expression of interferon genes, activating innate immune responses. c-di-GMP has been found in eukarotic systems acting not only in immune response, but as an inhibitor of the pacemaker I(f) current in the heart.