Premium
YpdC determines site‐1 degradation in regulated intramembrane proteolysis of the RsiW anti‐sigma factor of Bacillus subtilis
Author(s) -
Heinrich Janine,
Wiegert Thomas
Publication year - 2006
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.1365-2958.2006.05391.x
Subject(s) - biology , sigma factor , bacillus subtilis , regulon , proteolysis , proteases , mutant , transmembrane protein , gene , transmembrane domain , biochemistry , protease , microbiology and biotechnology , genetics , escherichia coli , rna polymerase , enzyme , bacteria , receptor
Summary Genes of Bacillus subtilis controlled by the alternative extracytoplasmic function family sigma factor σ W constitute an antibiosis regulon. Its activity is modulated by RsiW, a transmembrane anti‐sigma factor that sequesters and inactivates σ W . Upon a stress signal, RsiW is degraded by a mechanism of regulated intramembrane proteolysis. To identify genes which influence RsiW degradation, a transposon screen with a reporter fusion of the green fluorescent protein to RsiW was performed. Among several gene loci identified, the ypdC ( prsW ) gene displayed a strong effect on RsiW stability. In a ypdC null mutant, induction of σ W ‐controlled genes is abolished and site‐1 proteolysis of RsiW is completely blocked. Transcriptional analysis revealed that ypdC is a monocistronic gene, and the defect of σ W induction of the null mutant was complemented by ectopically integrated ypdC under xylose control. Orthologues of YpdC can be found in a variety of different bacteria. Its membrane topology was analysed by alkaline phosphatase fusions, revealing that YpdC contains five transmembrane segments and two larger extracytoplasmic loops. In the first loop, two invariantly conserved glutamate residues can be found. In an Escherichia coli system, the cloned ypdC is the only determinant of efficient degradation of RsiW; however, YpdC does not display plain similarities to known proteases, suggesting that it either controls the activity of site‐1 proteolysis of RsiW or represents a new type of protease.