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Quantifying Yersinia pseudotuberculosis Type III Secretion System Activity Following Iron Starvation and Anaerobic Growth
Published on: May 31, 2024
Extracytoplasmic-stress-responsive pathways modulate type III secretion in Yersinia pseudotuberculosis
Katrin E Carlsson1, Junfa Liu, Petra J Edqvist
1Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
Infection and Immunity
|May 23, 2007
Summary
The Cpx pathway is crucial for Yersinia pseudotuberculosis to secrete Yops via its type III secretion system. This pathway impacts the assembly and function of the secretion apparatus, affecting bacterial cytotoxicity.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Extracytoplasmic stress response pathways, including CpxRA, BaeSR, and sigma(E), are vital for bacterial adaptation.
- These pathways regulate protein homeostasis and the biogenesis of extracellular structures.
- The Ysc-Yop type III secretion system (T3SS) is essential for virulence in enteropathogens like Yersinia pseudotuberculosis.
Purpose of the Study:
- To investigate the role of extracytoplasmic stress response pathways (CpxRA, BaeSR, sigma(E)) in regulating the Ysc-Yop T3SS functionality in Yersinia pseudotuberculosis.
- To determine how these pathways influence the secretion and delivery of Yersinia outer proteins (Yops) into host cells.
Main Methods:
- Genetic disruption of individual components within the CpxRA and sigma(E) pathways.
- Analysis of Ysc secretion apparatus component levels in bacterial membranes.
- Assessment of Yop localization and effector function in eukaryotic cells.
- Construction and analysis of a cpxA lcrQ double mutant.
Main Results:
- Disruption of CpxRA and sigma(E) pathways significantly impaired Y. pseudotuberculosis T3SS-mediated Yop secretion.
- Loss of CpxA led to reduced levels of structural Ysc components, hindering secretion apparatus assembly.
- Mutant bacteria exhibited defects in Yop translocation into host cells, reducing cytotoxicity.
- A cpxA lcrQ double mutant remained impaired in host cell intoxication despite Yop overproduction.
Conclusions:
- The Cpx pathway plays a critical role in Y. pseudotuberculosis virulence by modulating Ysc-Yop T3SS function.
- Cpx pathway influences both the assembly of the secretion apparatus and the efficiency of effector protein delivery.
- These findings highlight the intricate regulation of bacterial secretion systems by stress response pathways, impacting host-pathogen interactions.
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