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PilJ localizes to cell poles and is required for type IV pilus extension in Pseudomonas aeruginosa

Paul A DeLange1, Tracy L Collins, George E Pierce

  • 1Biology Department, University of Dayton, 300 College Park, Dayton, OH 45469-2320, USA.

Current Microbiology
|August 24, 2007
PubMed

Insights

PilJ protein is essential for Pseudomonas aeruginosa twitching motility by regulating type IV pili (TFP) extension. PilJ localization at cell poles is crucial for proper TFP assembly and function.

Area of Science:

  • Microbiology
  • Cellular Biology
  • Bacterial Motility

Background:

  • Pseudomonas aeruginosa utilizes twitching motility, mediated by type IV pili (TFP), for surface-associated movement and environmental response.
  • PilJ protein shares sequence similarity with methyl-accepting chemotaxis proteins (MCPs) and is implicated in twitching motility.

Purpose of the Study:

  • To investigate the role of PilJ in the assembly and extension of type IV pili in Pseudomonas aeruginosa.
  • To determine the subcellular localization and behavior of PilJ within P. aeruginosa cells.

Main Methods:

  • Comparative analysis of wild-type and pilJ mutant Pseudomonas aeruginosa PAO1 strains.
  • Localization studies using yellow fluorescent protein (YFP) fusions of PilJ (pilJ-yfp), both on plasmids and chromosomally integrated.
  • Microscopy to observe pilus length, distribution, and PilJ-YFP localization.

Main Results:

  • PilJ is required for full type IV pili extension; pilJ mutants exhibit shortened pili, often at both poles, despite normal pilin levels.
  • PilJ localizes to both poles of the P. aeruginosa cell.
  • Overexpression of PilJ-YFP leads to its accumulation in the central region between the cell poles.

Conclusions:

  • PilJ plays a critical role in the proper assembly and/or extension of type IV pili in Pseudomonas aeruginosa.
  • The polar localization of PilJ suggests a specific role in regulating pilus dynamics at the cell periphery.

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