Clp ATPases are required for stress tolerance, intracellular replication and biofilm formation in Staphylococcus aureus

Mol Microbiol. 2004 Dec;54(5):1445-62. doi: 10.1111/j.1365-2958.2004.04368.x.


The Hsp100/Clp ATPases constitute a family of closely related proteins of which some members function solely as chaperones whereas others additionally can associate with the unrelated ClpP peptidase forming a Clp proteolytic complex. We have investigated the role of four Clp ATPases in the versatile pathogen, Staphylococcus aureus. Previously, we showed that ClpX is required for expression of major virulence factors and for virulence of S. aureus, but not for survival during heat shock. In the present study, we have inactivated clpC, clpB and clpL and, while none of these mutations affected toxin production, both ClpC and ClpB and to a minor extent ClpL were required for intracellular multiplication within bovine mammary epithelial cells. These defects were paralleled by an inability of the clpC mutant to grow at high temperature and of the clpB mutant to induce thermotolerance indicating that the protective functions of these proteins are required both at high temperature and during infection. By primer extension analysis and footprint studies, we show that expression of clpC and clpB is controlled by the negative heat-shock regulator, CtsR, and that ClpC is required for its repressor activity. Thus, ClpC is a likely sensor of stress encountered during both environmental stress and infection. In addition to virulence factor production the ability to form biofilms is of importance to S. aureus as a nosocomial pathogen. Interestingly, biofilm formation was reduced in the absence of ClpX or ClpC whereas it was enhanced in the absence of ClpP. Thus, our data show that Clp proteolytic complexes and the Clp ATPases control several key processes of importance to the success of S. aureus as a pathogen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Adaptation, Physiological
  • Adenosine Triphosphatases / genetics*
  • Adenosine Triphosphatases / physiology*
  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology
  • Bacterial Toxins / biosynthesis
  • Biofilms / growth & development
  • Cattle
  • Cells, Cultured
  • Endopeptidase Clp
  • Epithelial Cells / microbiology
  • Escherichia coli Proteins
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Heat-Shock Proteins / genetics*
  • Heat-Shock Proteins / physiology*
  • Hot Temperature
  • Molecular Chaperones
  • Repressor Proteins / metabolism
  • Sequence Deletion
  • Staphylococcus aureus / enzymology*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / growth & development
  • Virulence Factors / biosynthesis
  • Virulence Factors / genetics


  • Bacterial Proteins
  • Bacterial Toxins
  • ClpC protein, Bacteria
  • CtsR protein, bacteria
  • Escherichia coli Proteins
  • Heat-Shock Proteins
  • Molecular Chaperones
  • Repressor Proteins
  • Virulence Factors
  • Endopeptidase Clp
  • Adenosine Triphosphatases
  • ClpX protein, E coli
  • ATPases Associated with Diverse Cellular Activities