Dual Molecular Signals Mediate the Bacterial Response to Outer-Membrane Stress
Author(s)Lima, Santiago; Guo, Monica S.; Chaba, Rachna; Gross, Carol A.; Sauer, Robert T.
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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.
DepartmentMassachusetts Institute of Technology. Department of Biology
American Association for the Advancement of Science (AAAS)
Lima, Santiago, Monica S. Guo, Rachna Chaba, Carol A. Gross, and Robert T. Sauer. “Dual Molecular Signals Mediate the Bacterial Response to Outer-Membrane Stress.” Science 340, no. 6134 (May 16, 2013): 837–841.
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