Cyclic AMP Signaling in Mycobacteria.

All cells must adapt to changing conditions, and many use cyclic AMP (cAMP) as a second messenger to sense and respond to fluctuations in their environment. cAMP is made by adenylyl cyclases (ACs), and mycobacteria have an unusually large number of biochemically distinct ACs. cAMP is important for gene regulation in mycobacteria, and the ability to secrete cAMP into host macrophages during infection contributes to Mycobacterium tuberculosis pathogenesis. This article discusses the many roles of cAMP in mycobacteria and reviews what is known about the factors that contribute to production, destruction, and utilization of this important signal molecule. Special emphasis is placed on cAMP signaling in M. tuberculosis complex bacteria and its importance to M. tuberculosis during host infection.