Deletion of membrane-associated Asp23 leads to upregulation of cell wall stress genes in Staphylococcus aureus

Mol Microbiol. 2014 Sep;93(6):1259-68. doi: 10.1111/mmi.12733. Epub 2014 Aug 19.


With about 25 000 molecules per cell, Asp23 is one of the most abundant proteins in Staphylococcus aureus. Asp23 has been characterized as a protein that, following an alkaline shock, accumulates in the soluble protein fraction. Transcription of the asp23 gene is exclusively regulated by the alternative sigma factor σ(B) , which controls the response of the bacterium to environmental stress. Sequence analysis identified Asp23 as a member of the widely distributed Pfam DUF322 family, precluding functional predictions based on its sequence. Using fluorescence microscopy we found that Asp23 colocalized with the cell membrane of Staphylococcus aureus. Since Asp23 has no recognizable transmembrane spanning domains, we initiated a search for proteins that link Asp23 to the cell membrane. We identified SAOUHSC_02443 as the Asp23 membrane anchor and have renamed it AmaP (Asp23 membrane anchoring protein). Deletion of the asp23 gene led to an upregulation of the cell wall stress response. In summary, we have identified Asp23 as a membrane-associated protein and we suggest a function for Asp23 in cell envelope homoeostasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Membrane / metabolism
  • Cell Wall / genetics*
  • Conserved Sequence
  • Gene Expression Regulation, Bacterial
  • Molecular Sequence Data
  • Staphylococcus aureus / cytology
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / metabolism*


  • Bacterial Proteins
  • asp23 protein, Staphylococcus aureus

Associated data

  • GEO/GSE53134