The type VI secretion system: translocation of effectors and effector-domains

Curr Opin Microbiol. 2009 Feb;12(1):11-7. doi: 10.1016/j.mib.2008.11.010. Epub 2009 Jan 21.


A number of prominent Gram-negative bacteria use the type VI secretion system (T6SS) to transport proteins across the bacterial envelope. Rapid progress is being made in elucidating the structural components of the T6SS apparatus, and a few effectors have been reported to pass through it. However, this is not the complete story: a family of T6SS proteins, the VgrGs, share structural features with the cell-puncturing device of the T4 bacteriophage, and may be used in a similar fashion by bacteria to puncture host cell membranes and insert the T6SS apparatus into the host cytosol. Interestingly, a number of VgrGs contain C-terminal extensions with effector-domains. Thus, the T6SS may translocate soluble effectors, as well as VgrG effector-domains.

Publication types

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

MeSH terms

  • Bacterial Proteins / metabolism*
  • Bacteriophage T4 / physiology
  • Gram-Negative Bacteria / metabolism*
  • Macromolecular Substances / metabolism*
  • Membrane Transport Proteins / metabolism*
  • Sequence Homology
  • Virulence Factors / metabolism*


  • Bacterial Proteins
  • Macromolecular Substances
  • Membrane Transport Proteins
  • Virulence Factors