Variations on a theme: diverse N-acyl homoserine lactone-mediated quorum sensing mechanisms in gram-negative bacteria

Debra Smith, Jin-Hong Wang, Jane E Swatton, Peter Davenport, Bianca Price, Helga Mikkelsen, Hannah Stickland, Kahoko Nishikawa, Noémie Gardiol, David R Spring, Martin Welch

Research output: Contribution to journalReview articlepeer-review


Many Gram-negative bacteria employ a mechanism of cell-cell communication known as quorum sensing (QS). The role of QS is to enable the cells in a culture to coordinate their gene expression profile with changes in the population cell density. The best characterized mechanisms of QS employ N-acylated homoserine lactones (AHLs) as signalling molecules. These AHLs are made by enzymes known as LuxI homologs, and accumulate in the culture supernatant at a rate proportional to the increase in cell density. Once the AHL concentration exceeds a certain threshold value, these ligands bind to intracellular receptors known as LuxR homologs. The latter are transcriptional regulators, whose activity alters upon binding the AHL ligand, thereby eliciting a change in gene transcription. Over the last five years, it has become increasingly obvious that this is a rather simplistic view of AHL-dependent QS, and that in fact, there is considerable diversity in the way in which LuxI-R homologs operate. The aim of the current review is to describe these variations on the basic theme, and to show how functional genomics is revolutionizing our understanding of QS-controlled regulons.

Original languageEnglish
Pages (from-to)167-211
Number of pages45
JournalScience progress
Issue numberPt 3-4
Publication statusPublished - 2006


  • 4-Butyrolactone
  • Bacterial Proteins
  • Biofilms
  • Gene Expression Regulation, Bacterial
  • Gram-Negative Bacteria
  • Models, Biological
  • Population Density
  • Quorum Sensing
  • Transcription Factors
  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Review


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