L- Arginine in Pseudomonas aeruginosa controls c-di-GMP levels and biofilm formation

Biofilm lifestyle allows bacteria to resist to antimicrobial treatments and host defenses. The second messenger c-di-GMP controls biofilm formation and dispersion in response to environmental cues, including NO and nutrients [1]. Among nutrients, arginine is associated to chronic infections, biofilm/virulence and antibiotic resistance, being at the crossroad of many metabolic processes and acting as a substrate for NO production by the host immune system. We recently found that P. aeruginosa is able to perceive environmental arginine to decrease the intracellular levels of c-di-GMP via the RmcA (Redox regulator of c-di-GMP) protein [2, 3], a multidomain membrane protein. Moreover, we show that RmcA may perceive the metabolic status of the cell via FAD/FADH2 sensing via a redox-based switch. This evidence widens the impact of this nucleotide also in the re-shaping of the central metabolism. 1. Rinaldo et al. (2018). FEMS Microbiol Lett., 365(6). 2. Paiardini et. al. (2018) Proteins. 86(10): 1088-1096. 3. Mantoni et al. (2018) FEBS J. 285(20): 3815-3834.