Premium
An essential protease involved in bacterial cell‐cycle control
Author(s) -
Jenal Urs,
Fuchs Thomas
Publication year - 1998
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/17.19.5658
Subject(s) - caulobacter crescentus , biology , cell cycle , microbiology and biotechnology , cell division , proteases , protease , proteolysis , dna replication , biochemistry , cell , dna , enzyme
Proteolytic inactivation of key regulatory proteins is essential in eukaryotic cell‐cycle control. We have identified a protease in the eubacterium Caulobacter crescentus that is indispensable for viability and cell‐cycle progression, indicating that proteolysis is also involved in controlling the bacterial cell cycle. Mutants of Caulobacter that lack the ATP‐dependent serine protease ClpXP are arrested in the cell cycle before the initiation of chromosome replication and are blocked in the cell division process. ClpXP is composed of two types of polypeptides, the ClpX ATPase and the ClpP peptidase. Site‐directed mutagenesis of the catalytically active serine residue of ClpP confirmed that the proteolytic activity of ClpXP is essential. Analysis of mutants lacking ClpX or ClpP revealed that both proteins are required in vivo for the cell‐cycle‐dependent degradation of the regulatory protein CtrA. CtrA is a member of the response regulator family of two‐component signal transduction systems and controls multiple cell‐cycle processes in Caulobacter . In particular, CtrA negatively controls DNA replication and our findings suggest that specific degradation of the CtrA protein by the ClpXP protease contributes to G 1 ‐to‐S transition in this organism.