The Legionella pneumophila Incomplete Phosphotransferase System Is Required for Optimal Intracellular Growth and Maximal Expression of PmrA-Regulated Effectors

• Published in: Infection and immunity Vol. 85; no. 6
• Main Authors: Speiser, Yariv, Zusman, Tal, Pasechnek, Anna, Segal, Gil
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01-06-2017
• Subjects: Bacterial Proteins - genetics; Gene Deletion; Gene Expression Regulation, Bacterial; Humans; Legionella micdadei; Legionella pneumophila; Legionella pneumophila - enzymology; Legionella pneumophila - genetics; Legionella pneumophila - pathogenicity; Legionnaires' Disease - microbiology; Macrophages - microbiology; Molecular Pathogenesis; Phosphoenolpyruvate Sugar Phosphotransferase System - genetics; Phosphorylation; PmrA two-component system; Legionella; effector gene expression; phosphotransferase system (PTS)
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.00121-17

The nitrogen phosphotransferase system (PTS
) is a regulatory cascade present in many bacteria, where it controls different functions. This system is usually composed of three basic components: enzyme I
(EI
), NPr, and EIIA
(encoded by the
,
, and
genes, respectively). In
, as well as in many other
species, the EIIA
component is missing. However, we found that deletion mutations in both
and
are partially attenuated for intracellular growth. Furthermore, these two PTS
components were found to be required for maximal expression of effector-encoding genes regulated by the transcriptional activator PmrA. Genetic analyses which include the construction of single and double deletion mutants and overexpression of wild-type and mutated forms of EI
, NPr, and PmrA indicated that the PTS
components affect the expression of PmrA-regulated genes via PmrA and independently from PmrB and that EI
and NPr are part of the same cascade and require their conserved histidine residues in order to function. Furthermore, expression of the
EII
component in
resulted in a reduction in the levels of expression of PmrA-regulated genes which was completely dependent on the
PTS components and the
EII
conserved histidine residue. Moreover, reconstruction of the
PTS
indicated that EI
is phosphorylated by phosphoenolpyruvate (PEP) and transfers its phosphate to NPr. Our results demonstrate that the
incomplete PTS
is functional and involved in the expression of effector-encoding genes regulated by PmrA.