Proteomics Analysis: A Powerful Tool to Identify Proteome Phenotype and Proteome Signature in Enterococcus faecalis
Résumé
Abstract: The proteome is defined as the set of proteins that an organism can produce. By extrapolation, the "Proteome
Phenotype" corresponds to the set of proteins whose synthesis is modified (under- or over-expressed) in a genetically
altered cell. This approach has been successfully used to identify regulons in some Gram positive and Gram negative
bacteria but can also be carried out with cells mutated in non regulatory genes in parallel to physiological phenotype
studies. Over past ten years, such results have been obtained with several mutant strains of Enterococcus faecalis, a rogue
commensal-turned-pathogen and Gram positive bacteria. Systematic 2-D gel electrophoresis carried out with cells affected
in genes encoding stress proteins or transcriptional regulators such as CcpA, HypR, or TCSs (Two Component Systems)
allowed to characterize some members of these regulons and to identify pleiotrophic effects of some mutations. Moreover,
comparison of gels obtained with proteins extracted from cells harvested after exposure to different stress conditions
revealed "Stress Proteome Signatures" of E. faecalis. The availability of the E. faecalis proteome, updated in this review,
is the key database to utilize these results for biomedical applications. Indeed, 46 proteins are now characterized on a
master gel which allowed identification of some effectors of the stress response. Because E. faecalis is a member of the
gastrointestinal tract flora, such proteomics approach may help to understand how it is able to cope with different hostile
environments and then become a pathogen responsible for infections in the bloodstream, urinary tract, or surgical wound
infections.