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Clp‐mediated proteolysis in Gram‐positive bacteria is autoregulated by the stability of a repressor
Author(s) -
Krüger Elke,
Zühlke Daniela,
Witt Elke,
Ludwig Holger,
Hecker Michael
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.4.852
Subject(s) - repressor , biology , operon , derepression , protease , bacillus subtilis , heat shock protein , proteolysis , heat shock , transcription (linguistics) , gene , microbiology and biotechnology , transcription factor , biochemistry , gene expression , psychological repression , genetics , escherichia coli , bacteria , enzyme , linguistics , philosophy
The heat shock proteins ClpC and ClpP are subunits of an ATP‐dependent protease of Bacillus subtilis . Under non‐stressed conditions, transcription of the clpC and clpP genes is negatively regulated by CtsR, the global repressor of clp gene expression. Here, CtsR was proven to be a specific substrate of the ClpCP protease under stress conditions. Two proteins of former unknown function, McsA and McsB, which are also encoded by the clpC operon, act as modulators of CtsR repression. McsA containing zinc finger motifs stabilizes CtsR under non‐stressed conditions. McsB, a putative kinase, can inactivate CtsR by modification to remove the repressor from the DNA and to target CtsR for degradation by the ClpCP protease during stress. Thus, clp gene expression in Gram‐positive bacteria is autoregulated by a novel mechanism of controlled proteolysis, a circuit of down‐regulation by stabilization and protection of a transcription repressor, and induction by presenting the repressor to the protease. Thereby, the ClpC ATPase, a member of the Hsp100 family, was identified as a positive regulator of the heat shock response.