Type III protein secretion mechanism in mammalian and plant pathogens

Biochim Biophys Acta. 2004 Nov 11;1694(1-3):181-206. doi: 10.1016/j.bbamcr.2004.03.011.


The type III protein secretion system (TTSS) is a complex organelle in the envelope of many Gram-negative bacteria; it delivers potentially hundreds of structurally diverse bacterial virulence proteins into plant and animal cells to modulate host cellular functions. Recent studies have revealed several basic features of this secretion system, including assembly of needle/pilus-like secretion structures, formation of putative translocation pores in the host membrane, recognition of N-terminal/5' mRNA-based secretion signals, and requirement of small chaperone proteins for optimal delivery and/or expression of effector proteins. Although most of our knowledge about the TTSS is derived from studies of mammalian pathogenic bacteria, similar and unique features are learned from studies of plant pathogenic bacteria. Here, we summarize the most salient aspects of the TTSS, with special emphasis on recent findings.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology*
  • Gram-Negative Bacteria / pathogenicity*
  • Gram-Negative Bacteria / physiology
  • Gram-Negative Bacterial Infections / microbiology*
  • Mammals / microbiology
  • Membrane Transport Proteins / physiology*
  • Phylogeny
  • Plant Diseases / microbiology*
  • Protein Transport
  • Pseudomonas / physiology
  • Yersinia / physiology


  • Bacterial Proteins
  • Membrane Transport Proteins