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

ABSTRACT: In Gram-negative bacteria, outer-membrane integrity is essential for survival and is monitored by the ?(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 ?(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.

SUBMITTER: Lima S

PROVIDER: S-EPMC3928677 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

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

Lima Santiago S Guo Monica S MS Chaba Rachna R Gross Carol A CA Sauer Robert T RT

Science (New York, N.Y.) 20130501 6134

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 ...[more]

PMID: 23687042

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