Imaging type VI secretion-mediated bacterial killing

Cell Rep. 2013 Jan 31;3(1):36-41. doi: 10.1016/j.celrep.2012.11.027. Epub 2013 Jan 3.


In the environment, bacteria compete with each other for nutrient availability or to extend their ecological niche. The type VI secretion system contributes to bacterial competition by the translocation of antibacterial effectors from predators into prey cells. The T6SS assembles a dynamic structure-the sheath-wrapped around a tube constituted of the Hcp protein. It has been proposed that by cycling between extended and contracted conformations the sheath acts as a crossbow to propel the Hcp tube toward the target cell. While the sheath dynamics have been studied in monocultures, the activity of the T6SS has not been recorded in presence of the prey. Here, time-lapse fluorescence microscopy of cocultures demonstrates that prey cells are killed upon contact with predator cells. Additional experiments provide evidence that sheath contraction correlates with nearby cell fading and that prey lysis occurs within minutes after sheath contraction. The results support a model in which T6SS dynamics are responsible for T6SS effectors translocation into recipient cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Secretion Systems*
  • Bacteriolysis
  • Escherichia coli / cytology*
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism*
  • Green Fluorescent Proteins / metabolism
  • Microbial Viability*
  • Microscopy, Fluorescence


  • Bacterial Secretion Systems
  • Green Fluorescent Proteins