Dual Molecular Signals Mediate the Bacterial Response to Outer-Membrane Stress
In Gram-negative bacteria, outer-membrane integrity is essential for survival and is monitored by the σ[superscript E] stress-response system, which initiates damage-repair pathways. One activating signal is unassembled outer-membrane proteins. Using biochemical and genetic experiments in Escherichi...
| Main Authors: | , , , , |
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| Other Authors: | , |
| Format: | Article |
| Language: | English |
| Published: |
American Association for the Advancement of Science (AAAS),
2015-04-23T18:30:09Z.
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| Subjects: | |
| Online Access: | Get fulltext |
| Summary: | In Gram-negative bacteria, outer-membrane integrity is essential for survival and is monitored by the σ[superscript 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[superscript 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. National Institutes of Health (U.S.) (Grant AI-16892) National Institutes of Health (U.S.) (Grant GM-36278) |
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