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The Bacillus subtilis σ W anti‐sigma factor RsiW is degraded by intramembrane proteolysis through YluC
Author(s) -
Schöbel Susanne,
Zellmeier Stephan,
Schumann Wolfgang,
Wiegert Thomas
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04031.x
Subject(s) - sigma factor , biology , bacillus subtilis , proteolysis , mutant , transmembrane protein , regulon , transmembrane domain , microbiology and biotechnology , inner membrane , biochemistry , gene , escherichia coli , rna polymerase , genetics , membrane , receptor , bacteria , enzyme
Summary The Bacillus subtilis σ W regulon is induced by different stresses such as alkaline shock, salt shock, phage infection and certain antibiotics that affect cell wall biosynthesis. The activity of the alternative, extracytoplasmic function (ECF) sigma factor σ W is modulated by a specific anti‐sigma factor (RsiW or YbbM) encoded by the rsiW ( ybbM ) gene located immediately downstream of sigW . The RsiW membrane topology was determined, and a specific reporter system for RsiW function was constructed. Experiments using the yeast two‐hybrid system suggested a direct interaction of σ W with the cytoplasmic part of RsiW. Analysis of truncated forms of the RsiW protein revealed that σ W induction by alkaline shock is dependent on both the transmembrane and the extracytoplasmic domain of RsiW. Western blot and pulse–chase experiments demonstrated degradation of RsiW after an alkaline shock. A B. subtilis mutant strain deleted for the Escherichia coli yaeL orthologue yluC , encoding a transmembrane protease, was defective in inducing a σ W ‐controlled promoter after alkaline shock and accumulated a membrane‐bound truncated form of RsiW, suggesting that the activity of σ W is controlled by the proteolysis of RsiW by at least two different proteolytic steps.