ClpP protease modulates bacterial growth, stress response and bacterial virulence in Brucella abortus

Intracellular proteolysis via ATP-dependent proteases is a conserved biological process. The ATP-dependent Clp protease is made up of peptidase ClpP and ATP-dependent chaperones and plays an important role in the proteolysis process. In several pathogenic bacteria, the Clp protease is implicated in the stress reponses and contributes to the bacterial virulence. In brucella abortus, the ΔclpP mutant strain exhibited a pronounced growth defect in TSB medium and the results showed that the ΔclpP mutant was sensitive to high temperature, high osmotic environment and iron deficient environment. In addition, deletion of the clpP significantly affected Brucella virulence in macrophage and mice infection models. Based on the iTRAQ analysis, the different expressed proteins were mainly involved in amino acid transport and metabolism, energy production and conversion, and secondary metabolites biosynthesis, transport and catabolism. Overall, our study revealed preliminary molecular mechanism between Clp protease, bacterial growth, stress response and bacterial virulence in Brucella strains