Cytokeratin 8 interacts with clumping factor B: a new possible virulence factor target

Microbiology (Reading). 2010 Dec;156(Pt 12):3710-3721. doi: 10.1099/mic.0.034413-0. Epub 2010 Sep 3.


Staphylococcus aureus is a human pathogen of growing clinical significance, owing to its increasing levels of resistance to most antibiotics. Infections range from mild wound infections to severe infections such as endocarditis, osteomyelitis and septic shock. Adherence of S. aureus to human host cells is an important step, leading to colonization and infection. Adherence is mediated by a multiplicity of proteins expressed on the bacterial surface, including clumping factor B. In this study, we aimed to identify new targets of clumping factor B in human keratinocytes by undertaking a genome-wide yeast two-hybrid screen of a human keratinocyte cDNA library. We show that clumping factor B is capable of binding cytokeratin 8 (CK8), a type II cytokeratin. Using a domain-mapping strategy we identified amino acids 437-464 as necessary for this interaction. Recombinantly expressed fragments of both proteins were used in pull-down experiments and confirmed the yeast two-hybrid studies. Analysis with S. aureus strain Newman deficient in clumping factor B showed the clumping factor B-dependence of the interaction with CK8. We postulate that the clumping factor B-CK8 interaction is a novel factor in S. aureus infections.

MeSH terms

  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / metabolism*
  • Amino Acid Sequence
  • Cell Line
  • Humans
  • Keratin-8 / genetics
  • Keratin-8 / metabolism*
  • Keratinocytes / metabolism
  • Keratinocytes / microbiology
  • Molecular Sequence Data
  • Protein Binding
  • Staphylococcal Infections / genetics
  • Staphylococcal Infections / metabolism*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / metabolism*
  • Staphylococcus aureus / pathogenicity
  • Two-Hybrid System Techniques
  • Virulence Factors / genetics
  • Virulence Factors / metabolism*


  • Adhesins, Bacterial
  • Keratin-8
  • Virulence Factors
  • clfB protein, Staphylococcus aureus