Revisiting old friends: updates on the role of two-component signaling systems in Listeria monocytogenes survival and pathogenesis
Xiomarie Alejandro-Navarreto and Nancy E. Freitag
Abstract
Listeria monocytogenes is well recognized for both its broad resistance to stress conditions and its ability to transition from a soil bacterium to an intracellular pathogen of mammalian hosts. The bacterium’s impressive ability to adapt to changing environments and conditions requires the rapid sensing of environmental cues and the coordinated response of gene products that enable bacterial growth and survival. Two component signaling systems (TCS) have been long recognized for their ability to detect environmental stimuli and transmit those signals into transcriptional responses, however often the precise nature of the stimulus triggering TCS responses can be challenging to define. L. monocytogenes has up to sixteen TCS that have been recognized based on homology and included in this list are several whose functions remain poorly described. This review highlights current understanding of the breadth and scope of L. monocytogenes TCS as relates to stress resistance and pathogenesis. Precise signals still often remain elusive, but the gene networks associated with TCS are providing clues into possible functions.