Journal of Biomedical Science

, Volume 12, Issue 4, pp 587–599 | Cite as

Roles of the Minor Pseudopilins, XpsH, XpsI and XpsJ, in the Formation of XpsG-Containing Pseudopilus in Xanthomonas campestris pv. Campestris

  • Wei-Wen Kuo
  • Hung-Wei Kuo
  • Chun-Chia Cheng
  • Hsiang-Ling Lai
  • Ling-Yun Chen


Due to their similarity to type IV pilus (Tfp) subunits, the pseudopilins, XpsG, -H, -I, -J and -K, have been predicted to form a pilus-like structure in the type II secretion (T2S) pathway. While overexpression of GspG can result in the formation of bundle structures, the functions of other pseudopilin are not known yet. In this study, we investigate the mutual interaction among the pseudopilins and characterize the specialized minor pseudopilin, XpsJ. By using gel filtration and Ni-NTA affinity chromatography, a linearly ordered interactive relationship is revealed among the four pseudopilins, XpsG-XpsI-XpsH-XpsJ. Notably, unlike the mutant XpsJ194 staying in the inner membrane, wild type XpsJ stayed in the outer membrane and blocked the extension of overexpressed XpsG to outside of the cell. By analogy with the Type I pilus structures, we hypothesize that the XpsH and XpsI might act as an adaptor to connect XpsJ with the major pseudopilin XpsG, and XpsJ might act as a tip to restrict the out-growth of XpsG in the pilus-like structure of the T2S pathway.


major pseudopilin minor pseudopilin tip type IV pili type I pili type II secretion pathway 


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Copyright information

© National Science Council, Taipei 2005

Authors and Affiliations

  • Wei-Wen Kuo
    • 1
  • Hung-Wei Kuo
    • 1
  • Chun-Chia Cheng
    • 1
  • Hsiang-Ling Lai
    • 1
  • Ling-Yun Chen
    • 1
  1. 1.Institute of BiochemistryChung Shan Medical UniversityTaiwanRepublic of China

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