Logo image
RtsA coordinately regulates DsbA and the Salmonella pathogenicity island 1 type III secretion system
Journal article   Open access   Peer reviewed

RtsA coordinately regulates DsbA and the Salmonella pathogenicity island 1 type III secretion system

Craig D Ellermeier and James M Slauch
Journal of bacteriology, Vol.186(1), pp.68-79
01/2004
DOI: 10.1128/JB.186.1.68-79.2004
PMCID: PMC303435
PMID: 14679226
url
https://doi.org/10.1128/JB.186.1.68-79.2004View
Published (Version of record) Open Access

Abstract

Salmonella serovars cause a wide variety of diseases ranging from mild gastroenteritis to life-threatening systemic infections. An important step in Salmonella enterica serovar Typhimurium infection is the invasion of nonphagocytic epithelial cells, mediated by a type III secretion system (TTSS) encoded on Salmonella pathogenicity island 1 (SPI1). The SPI1 TTSS forms a needle complex through which effector proteins are injected into the cytosol of host cells, where they promote actin rearrangement and engulfment of the bacteria. We previously identified the Salmonella-specific regulatory protein RtsA, which induces expression of hilA and, thus, the SPI1 genes. Here we show that the hilA regulators RtsA, HilD, and HilC can each induce transcription of dsbA, which encodes a periplasmic disulfide bond isomerase. RtsA induces expression of dsbA independent of either the SPI1 TTSS or the only known regulator of dsbA, the CpxRA two-component system. We show that DsbA is required for both the SPI1 and SPI2 TTSS to translocate effector proteins into the cytosol of host cells. DsbA is also required for survival during the systemic stages of infection. We also present evidence that production of SPI1 effector proteins is coupled to assembly of the TTSS. This feedback regulation is mediated at either the transcriptional or posttranscriptional level, depending on the particular effector. Loss of DsbA leads to feedback inhibition, which is consistent with the hypothesis that disulfide bond formation plays a role in TTSS assembly or function.
Salmonella typhimurium - genetics Salmonella typhimurium - pathogenicity Protein Disulfide-Isomerases - metabolism Virulence Bacterial Proteins - genetics Transcription Factors - genetics Salmonella Infections, Animal - physiopathology Salmonella typhimurium - metabolism Transcription Factors - metabolism Protein Disulfide-Isomerases - genetics Animals Salmonella Infections, Animal - microbiology Trans-Activators - genetics Bacterial Proteins - metabolism Female Trans-Activators - metabolism Mice Mice, Inbred BALB C Gene Expression Regulation, Bacterial

Details

Metrics

Logo image