Send to

Choose Destination
Science. 2013 May 17;340(6134):837-41. doi: 10.1126/science.1235358.

Dual molecular signals mediate the bacterial response to outer-membrane stress.

Author information

Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.


In Gram-negative bacteria, outer-membrane integrity is essential for survival and is monitored by the σ(E) stress-response system, which initiates damage-repair pathways. One activating signal is unassembled outer-membrane proteins. Using biochemical and genetic experiments in Escherichia coli, we found that off-pathway intermediates in lipopolysaccharide transport and assembly provided an additional required signal. These distinct signals, arising from disruptions in the transport and assembly of the major outer-membrane components, jointly determined the rate of proteolytic destruction of a negative regulator of the σ(E) transcription factor, thereby modulating the expression of stress-response genes. This dual-signal system permits a rapid response to dysfunction in outer-membrane biogenesis, while buffering responses to transient fluctuations in individual components, and may represent a broad strategy for bacteria to monitor their interface with the environment.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center