Type III Secretion in the Melioidosis Pathogen Burkholderia pseudomallei

Charles W. Vander Broek, Joanne M. Stevens

Research output: Contribution to journalLiterature reviewpeer-review

Abstract

Burkholderia pseudomallei is a Gram-negative intracellular pathogen and the causative agent of melioidosis, a severe disease of both humans and animals. Melioidosis is an emerging disease which is predicted to be vastly under-reported. Type III Secretion Systems (T3SSs) are critical virulence factors in Gram negative pathogens of plants and animals. The genome of B. pseudomallei encodes three T3SSs. T3SS-1 and -2, of which little is known, are homologous to Hrp2 secretion systems of the plant pathogens Ralstonia and Xanthomonas. T3SS-3 is better characterized and is homologous to the Inv/Mxi-Spa secretion systems of Salmonella spp. and Shigella flexneri,respectively. Upon entry into the host cell, B. pseudomallei requires T3SS-3 for efficient escape from the endosome. T3SS-3 is also required for full virulence in both hamster and murine models of infection. The regulatory cascade which controls T3SS-3 expression and the secretome of T3SS-3 have been described, as well as the effect of mutations of some of the structural proteins. Yet only a few effector proteins have been functionally characterized to date and very little work has been carried out to understand the hierarchy of assembly, secretion and temporal regulation of T3SS-3. This review aims to frame current knowledge of B. pseudomallei T3SSs in the context of other well characterized model T3SSs, particularly those of Salmonella and Shigella.

Original languageEnglish
Article number255
Number of pages17
JournalFrontiers in Cellular and Infection Microbiology
Volume7
DOIs
Publication statusPublished - 15 Jun 2017

Keywords

  • T3SS
  • effector
  • translocator
  • Burkholderia pseudomallei
  • melioidosis
  • ENTERICA SEROVAR TYPHIMURIUM
  • INTRACELLULAR LIFE-CYCLE
  • SYSTEM NEEDLE TIP
  • NF-KAPPA-B
  • SHIGELLA-FLEXNERI
  • SALMONELLA-TYPHIMURIUM
  • ESCHERICHIA-COLI
  • YERSINIA-PSEUDOTUBERCULOSIS
  • PROTEIN SECRETION
  • HOST-CELLS

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