Seek, Sense, and Destroy

Science's STKE  04 Jan 2005:
Vol. 2005, Issue 265, pp. tw12
DOI: 10.1126/stke.2652005tw12

Highly virulent enterococcal strains have a pathogenicity island within their genome that encodes, among other traits, a cytolytic toxin that uses a quorum-sensing mechanism to affect autoinduction. Coburn et al. (see the Perspective by Garsin) show that the bacterium actively secretes two components, an autoinducer and an anti-autoinducer. In the absence of target cells, these two interact and prevent the autoinducer from feeding back to induce high-level expression of the cytolysin. In the presence of the target cell, however, the anti-autoinducer binds to the target cell and allows the autoinducer to accumulate to the threshold level required for quorum induction of the cytolysin operon. The anti-autoinducer is itself a toxin component and effectively tags the target for destruction.

P. S. Coburn, C. M. Pillar, B. D. Jett, W. Haas, M. S. Gilmore, Enterococcus faecalis senses target cells and in response expresses cytolysin. Science 306, 2270-2272 (2004). [Abstract] [Full Text]

D. A. Garsin, Peptide signals sense and destroy target cells. Science 306, 2202-2203 (2004). [Summary] [Full Text]