Unsaturated long-chain free fatty acids are input signals of the Salmonella enterica PhoP/PhoQ regulatory system

VIARENGO, G; SCIARA, M; SALAZAR, MO; KIEFFER, PM; FURLAN, RLE; GARCIA VESCOVI, E

JOURNAL OF BIOLOGICAL CHEMISTRY

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Lugar: Bethesda, Maryland; Año: 2013 vol. 288 p. 22346 - 22358

0021-9258

Salmonella enterica serovar Typhimurium PhoP/PhoQ system has largely been studied as a paradigmatic two-component regulatory system not only to dissect structural and functional aspects of signal transduction in bacteria, but also to gain knowledge about the versatile devices that have evolved allowing a pathogenic bacterium to adjust to or counteract environmental stressful conditions along its life cycle. limitation, acidic pH and the presence of cationic antimicrobial peptides have been identified as cues that the sensor protein PhoQ can monitor to reprogram Salmonella gene expression and cope with the survival challenges encountered in extra- or intra-cellular niches. In this work, we demonstrate for the first time that long chain unsaturated free fatty acids present in Salmonella growth medium are specifically detected as PhoQ signals that inhibit the autokinase activity of the sensor protein, turning off the PhoP-dependent regulon expression.Our finding puts forth the complexity of input signals that can converge to finely tune the activity of the PhoP/PhoQ system, reflecting the variety of ambient conditions that Salmonella faces in host and non-host environments. Besides, they provide a new potential biochemical platform for the development of an antibacterial strategy to fight against Salmonella infections.