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tRNA modification enzyme MiaB connects environmental cues to activation of Pseudomonas aeruginosa type III secretion

Qiqi Lin1,2,3, Jiahui Huang1,2, Zhiqing Liu1,2

  • 1Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.

Plos Pathogens
|December 5, 2022
PubMed

Insights

The tRNA modification enzyme MiaB positively regulates the Type III Secretion System (T3SS) in Pseudomonas aeruginosa, crucial for bacterial virulence. MiaB integrates environmental signals to control T3SS gene expression and cytotoxicity.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections.
  • The Type III Secretion System (T3SS) is a key virulence factor for P. aeruginosa.
  • T3SS regulation by environmental cues like spermidine is known but incompletely understood.

Purpose of the Study:

  • To elucidate the regulatory mechanism of T3SS gene expression in P. aeruginosa.
  • To identify novel factors involved in T3SS regulation under changing environmental conditions.

Main Methods:

  • Genetic assays were used to investigate the role of the tRNA modification enzyme PA3980 (MiaB).
  • The study examined MiaB's interaction with the LadS-Gac/Rsm signaling pathway and the ExsA regulator.
  • Expression analysis was performed to understand MiaB induction by Vfr and spermidine signaling.

Main Results:

  • MiaB was identified as a positive regulator of T3SS gene expression and essential for P. aeruginosa cytotoxicity.
  • MiaB represses the LadS-Gac/Rsm pathway and acts through the ExsA regulator to promote T3SS expression.
  • MiaB expression is induced by Vfr and spermidine signaling, integrating these cues for T3SS regulation.

Conclusions:

  • MiaB represents a novel regulatory mechanism for T3SS in P. aeruginosa.
  • MiaB integrates environmental signals to modulate T3SS gene expression, impacting bacterial virulence.
  • This finding provides new insights into the pathogenesis of P. aeruginosa infections.

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