Type I signal peptidase and protein secretion in Staphylococcus aureus

J Bacteriol. 2012 May;194(10):2677-86. doi: 10.1128/JB.00064-12. Epub 2012 Mar 23.

Abstract

Staphylococcus aureus is an important human pathogen whose virulence relies on the secretion of many different proteins. In general, the secretion of most proteins in S. aureus, as well as other bacteria, is dependent on the type I signal peptidase (SPase)-mediated cleavage of the N-terminal signal peptide that targets a protein to the general secretory pathway. The arylomycins are a class of natural product antibiotics that inhibit SPase, suggesting that they may be useful chemical biology tools for characterizing the secretome. While wild-type S. aureus (NCTC 8325) is naturally resistant to the arylomycins, sensitivity is conferred via a point mutation in its SPase. Here, we use a synthetic arylomycin along with a sensitized strain of S. aureus and multidimensional protein identification technology (MudPIT) mass spectrometry to identify 46 proteins whose extracellular accumulation requires SPase activity. Forty-four possess identifiable Sec-type signal peptides and thus are likely canonically secreted proteins, while four also appear to possess cell wall retention signals. We also identified the soluble C-terminal domains of two transmembrane proteins, lipoteichoic acid synthase, LtaS, and O-acyteltransferase, OatA, both of which appear to have noncanonical, internal SPase cleavage sites. Lastly, we identified three proteins, HtrA, PrsA, and SAOUHSC_01761, whose secretion is induced by arylomycin treatment. In addition to elucidating fundamental aspects of the physiology and pathology of S. aureus, the data suggest that an arylomycin-based therapeutic would reduce virulence while simultaneously eradicating an infection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial / drug effects
  • Gene Expression Regulation, Bacterial / physiology*
  • Gene Expression Regulation, Enzymologic / physiology*
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Oligopeptides / chemistry
  • Oligopeptides / pharmacology
  • Peptides, Cyclic / chemistry
  • Peptides, Cyclic / pharmacology
  • Point Mutation
  • Protein Conformation
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism*
  • Staphylococcus aureus / enzymology*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / metabolism*
  • Virulence Factors

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Membrane Proteins
  • Oligopeptides
  • Peptides, Cyclic
  • Virulence Factors
  • arylomycin A-C16
  • Serine Endopeptidases
  • type I signal peptidase