Lateral density of receptor arrays in the membrane plane influences sensitivity of the E. coli chemotaxis response

EMBO J. 2011 May 4;30(9):1719-29. doi: 10.1038/emboj.2011.77. Epub 2011 Mar 25.

Abstract

In chemotactic bacteria, transmembrane chemoreceptors, CheA and CheW form the core signalling complex of the chemotaxis sensory apparatus. These complexes are organized in extended arrays in the cytoplasmic membrane that allow bacteria to respond to changes in concentration of extracellular ligands via a cooperative, allosteric response that leads to substantial amplification of the signal induced by ligand binding. Here, we have combined cryo-electron tomographic studies of the 3D spatial architecture of chemoreceptor arrays in intact E. coli cells with computational modelling to develop a predictive model for the cooperativity and sensitivity of the chemotaxis response. The predictions were tested experimentally using fluorescence resonance energy transfer (FRET) microscopy. Our results demonstrate that changes in lateral packing densities of the partially ordered, spatially extended chemoreceptor arrays can modulate the bacterial chemotaxis response, and that information about the molecular organization of the arrays derived by cryo-electron tomography of intact cells can be translated into testable, predictive computational models of the chemotaxis response.

Publication types

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

MeSH terms

  • Bacterial Proteins / metabolism*
  • Blotting, Western
  • Chemotaxis / physiology*
  • Cryoelectron Microscopy
  • Escherichia coli / metabolism
  • Escherichia coli / physiology*
  • Escherichia coli Proteins
  • Fluorescence Resonance Energy Transfer
  • Histidine Kinase
  • Ligands
  • Membrane Proteins / metabolism*
  • Methyl-Accepting Chemotaxis Proteins
  • Models, Molecular*
  • Multiprotein Complexes / metabolism*
  • Multiprotein Complexes / physiology
  • Signal Transduction / physiology*

Substances

  • Bacterial Proteins
  • Escherichia coli Proteins
  • Ligands
  • Membrane Proteins
  • Methyl-Accepting Chemotaxis Proteins
  • Multiprotein Complexes
  • Histidine Kinase
  • cheA protein, E coli