Aim, Load, Fire: The Type VI Secretion System, a Bacterial Nanoweapon

Trends Microbiol. 2016 Jan;24(1):51-62. doi: 10.1016/j.tim.2015.10.005. Epub 2015 Nov 5.


Bacteria utilise specialised protein secretion systems to interact with host organisms, competitor bacteria, and the environment. The Type VI secretion system (T6SS) is a versatile weapon deployed by many bacterial species to target either host cells or rival bacteria. The widespread occurrence and significance of the T6SS is becoming increasingly appreciated, as is its intriguing mode of action. The T6SS delivers multiple, diverse effector proteins directly into target cells using a dynamic 'firing' mechanism related to the action of contractile bacteriophage tails. Here, we summarise the contribution of recent findings to our developing picture of how the T6SS assembles and fires, how it is loaded with different types of effectors, and how it can be aimed towards an incoming assault.

Keywords: bacterial protein secretion; interbacterial competition; macromolecular machine; secreted effector proteins; type VI secretion system.

Publication types

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

MeSH terms

  • Bacteria / metabolism*
  • Bacterial Proteins / physiology*
  • Bacteriophages / physiology
  • Models, Molecular
  • Nanostructures / microbiology
  • Type VI Secretion Systems / physiology*


  • Bacterial Proteins
  • Type VI Secretion Systems