The chaperone ClpX stimulates expression of Staphylococcus aureus protein A by Rot dependent and independent pathways

• Published in: PloS one Vol. 5; no. 9; p. e12752
• Main Authors: Jelsbak, Lotte, Ingmer, Hanne, Valihrach, Lukás, Cohn, Marianne Thorup, Christiansen, Mie H G, Kallipolitis, Birgitte H, Frees, Dorte
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14-09-2010; Public Library of Science (PLoS)
• Subjects: Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; Antibodies; ATPases; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biochemistry; Chaperones; Cloning; Disease; E coli; Escherichia coli; Gene expression; Gene Expression Regulation, Bacterial; Heat shock proteins; Helicobacter pylori; Infectious Diseases/Bacterial Infections; Laboratories; Life sciences; Microbiology; Microbiology/Cellular Microbiology and Pathogenesis; Molecular biology; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Plasmids; Protein A; Proteins; Repressor Proteins - genetics; Repressor Proteins - metabolism; RNA; Rot; Staphylococcal Protein A - genetics; Staphylococcal Protein A - metabolism; Staphylococcus aureus; Staphylococcus aureus - enzymology; Staphylococcus aureus - genetics; Staphylococcus aureus - metabolism; Staphylococcus aureus infections; Staphylococcus infections; Transcription; Translation; Translation (Genetics); Virulence
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0012752

The Clp ATPases (Hsp100) constitute a family of closely related proteins that have protein reactivating and remodelling activities typical of molecular chaperones. In Staphylococcus aureus the ClpX chaperone is essential for virulence and for transcription of spa encoding Protein A. The present study was undertaken to elucidate the mechanism by which ClpX stimulates expression of Protein A. For this purpose, we prepared antibodies directed against Rot, an activator of spa transcription, and demonstrated that cells devoid of ClpX contain three-fold less Rot than wild-type cells. By varying Rot expression from an inducible promoter we showed that expression of Protein A requires a threshold level of Rot. In the absence of ClpX the Rot content is reduced below this threshold level, hence, explaining the substantially reduced Protein A expression in the clpX mutant. Experiments addressed at pinpointing the role of ClpX in Rot synthesis revealed that ClpX is required for translation of Rot. Interestingly, translation of the spa mRNA was, like the rot mRNA, enhanced by ClpX. These data demonstrate that ClpX performs dual roles in regulating Protein A expression, as ClpX stimulates transcription of spa by enhancing translation of Rot, and that ClpX additionally is required for full translation of the spa mRNA. The current findings emphasize that ClpX has a central role in fine-tuning virulence regulation in S. aureus.