The Escherichia coli sigma(E)-dependent extracytoplasmic stress response is controlled by the regulated proteolysis of an anti-sigma factor.
The activity of the stress-responsive sigma factor, sigma(E), is induced by the extracytoplasmic accumulation of misfolded or unfolded protein. The inner membrane protein RseA is the central regulatory molecule in this signal transduction cascade and acts as a sigma(E)-specific anti-sigma factor. Here we show that sigma(E) activity is primarily determined by the ratio of RseA to sigma(E). RseA is rapidly degraded in response to extracytoplasmic stress, leading to an increase in the free pool of sigma(E) and initiation of the stress response. We present evidence that the putative inner membrane serine protease, DegS, is responsible for this regulated degradation of RseA.
Ades
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Department of Stomatology, University of California at San Francisco, San Francisco, California 94143 USA.
Connolly
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LE
Alba
B M
BM
Gross
C A
CA
D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D008565:Membrane Proteins / Q000096:biosynthesis / Q000378:metabolism; D016296:Mutagenesis; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D012808:Sigma Factor / Q000096:biosynthesis / Q000502:physiology*; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000502:physiology*
D001426:Bacterial Proteins; C066496:DegS protein, Bacteria; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C489349:degS protein, Escherichia coli; C063202:sporulation-specific sigma factors