Nucleotide second messengers are key components of the signal transduction networks that link sensory input with the regulatory output responses of all living cells. While research with bacteria has provided early textbook examples such as cyclic AMP and (p)ppGpp, which control genome-wide gene expression, the astonishing diversity, mechanistic complexity and pervasive roles of bacterial second messenger signaling have become apparent only recently. This dramatic progress has been triggered by the discovery of the cyclic dinucleotide c-di-GMP as a ubiquitous ‘life-style’ signaling molecule that promotes adhesion and biofilm formation while antagonizing motility of single planktonic cells. Moreover, c-di-GMP also controls bacterial cell cycle progression, development and virulence.

Research on c-di-GMP currently represents one of the most dynamic fields in molecular microbiology and has sparked intense interest also in other nucleotide-based second messengers leading to the recent identification of c-di-AMP and c-GMP-AMP in bacteria as well as the characterization of their modes of action.

The SPP 1879 research programme includes projects dealing with the biosynthesis, turnover and functions of c-di-GMP, the ‘classics’ cAMP and ppGpp, as well as the very recently identified novel second messengers such as c-di-AMP, which are being studied from molecular, cellular, physiological, systems-level and ecological perspectives.