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IreK-Mediated, Cell Wall-Protective Phosphorylation in Enterococcus faecalis

Anthony A Iannetta1, Nicole E Minton2, Alexis A Uitenbroek2

  • 1Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.

Journal of Proteome Research
|October 21, 2021
PubMed

Insights

Enterococcus faecalis uses the IreK kinase to resist antibiotics by altering cell division and peptidoglycan synthesis. This study identifies key IreK substrates, revealing mechanisms of antimicrobial resistance.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Enterococcus faecalis is a significant cause of hospital-acquired infections.
  • Its intrinsic resistance to antimicrobials, particularly cell wall-active drugs, is a major clinical challenge.
  • The transmembrane kinase IreK is implicated in this resistance but its direct substrates are largely unknown.

Purpose of the Study:

  • To investigate stress-modulated phosphorylation events in E. faecalis contributing to antimicrobial resistance.
  • To identify direct substrates of the IreK kinase.
  • To elucidate the role of IreK in regulating cell wall homeostasis and antimicrobial resistance.

Main Methods:

  • Phosphoproteomics analysis of wild-type E. faecalis cells treated with chlorhexidine or ceftriaxone.
  • Comparative phosphoproteomics analysis using an E. faecalis ΔireK mutant strain.
  • Identification of differentially phosphorylated proteins and potential IreK substrates.

Main Results:

  • Cell wall stress induced by antimicrobials leads to increased phosphorylation of divisome components in E. faecalis.
  • IreK-mediated phosphorylation affects components involved in peptidoglycan biosynthesis.
  • Potential IreK substrates were identified within the CroS/R two-component system, a known antimicrobial resistance pathway.

Conclusions:

  • E. faecalis modulates cell division in response to cell wall stress, involving IreK.
  • IreK plays a critical role in regulating peptidoglycan biosynthesis and antimicrobial resistance.
  • These findings provide crucial insights into the biological functions of IreK and potential targets for combating E. faecalis infections.
Keywords:
Enterococcus faecalisIreKPASTA kinaseantimicrobial resistancecell wall stressmass spectrometryphosphoproteomics

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