Type VI secretion requires a dynamic contractile phage tail-like structure

Nature. 2012 Feb 26;483(7388):182-6. doi: 10.1038/nature10846.


Type VI secretion systems are bacterial virulence-associated nanomachines composed of proteins that are evolutionarily related to components of bacteriophage tails. Here we show that protein secretion by the type VI secretion system of Vibrio cholerae requires the action of a dynamic intracellular tubular structure that is structurally and functionally homologous to contractile phage tail sheath. Time-lapse fluorescence light microscopy reveals that sheaths of the type VI secretion system cycle between assembly, quick contraction, disassembly and re-assembly. Whole-cell electron cryotomography further shows that the sheaths appear as long tubular structures in either extended or contracted conformations that are connected to the inner membrane by a distinct basal structure. These data support a model in which the contraction of the type VI secretion system sheath provides the energy needed to translocate proteins out of effector cells and into adjacent target cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / ultrastructure*
  • Bacterial Secretion Systems / physiology*
  • Bacteriophages / chemistry*
  • Bacteriophages / physiology
  • Cell Membrane / metabolism
  • Cryoelectron Microscopy
  • Electron Microscope Tomography
  • Microscopy, Fluorescence
  • Vibrio cholerae / chemistry*
  • Vibrio cholerae / cytology
  • Vibrio cholerae / metabolism*
  • Vibrio cholerae / ultrastructure


  • Bacterial Proteins
  • Bacterial Secretion Systems