The Journal of Membrane Biology

, Volume 151, Issue 2, pp 175–187

Multiple Mechanosensitive Ion Channels from Escherichia coli, Activated at Different Thresholds of Applied Pressure

  • C.  Berrier
  • M.  Besnard
  • B.  Ajouz
  • A.  Coulombe
  • A.  Ghazi

DOI: 10.1007/s002329900068

Cite this article as:
Berrier, C., Besnard, M., Ajouz, B. et al. J. Membrane Biol. (1996) 151: 175. doi:10.1007/s002329900068

Abstract.

Mechanosensitive ion channels from Escherichia coli were studied in giant proteoliposomes reconstituted from an inner membrane fraction, or in giant round cells in which the outer membrane and the cell wall had been disrupted by a lysozyme-EDTA treatment and a mild osmotic shock. Patch-clamp experiments revealed the presence in these two preparations of an array of different conductances (100 to 2,300 pS in 0.1 m KCl) activated by stretch. The electrical activity induced by stretch in the native membrane was complex, due to the activation of several different conductances. In contrast, patches of proteoliposomes generally contained clusters of identical conductances, which differed from patch to patch. These experiments are consistent with the notion that these different conductances correspond to different proteins in the plasma membrane of E. coli, which segregate into clusters of identical channels on dilution involved in reconstitution in proteoliposomes. These conductances could be grouped into three subfamilies of poorly selective channels. In both preparations, the higher the conductance, the higher was the negative pressure needed for activation. We discuss the putative role of these channels as parts of a multicomponent osmoregulatory system.

Key words: Mechanosensitive ion channels —Escherichia coli— Bacteria — Osmoregulation — Patch-clamp — Liposomes 

Copyright information

© 1996 Springer-Verlag New York Inc.

Authors and Affiliations

  • C.  Berrier
    • 1
  • M.  Besnard
    • 1
  • B.  Ajouz
    • 1
  • A.  Coulombe
    • 2
  • A.  Ghazi
    • 1
  1. 1.Laboratoire des Biomembranes, URA CNRS 1116, Bât. 432, Université Paris-Sud, 91405 Orsay, FranceFR
  2. 2.Hôpital M. Lannelongue, URA CNRS 1159, 92350 Le Plessis Robinson, FranceFR