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Immunofluorescence Analysis of Stress Granule Formation After Bacterial Challenge of Mammalian Cells
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Immunofluorescence Analysis of Stress Granule Formation After Bacterial Challenge of Mammalian Cells

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Activation of cell stress response pathways by Shiga toxins

Vernon L Tesh1

  • 1Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M Health Science Center, Bryan, TX 77807, USA. tesh@medicine.tamhsc.edu

Cellular Microbiology
|September 9, 2011
PubMed

Insights

Shiga toxins (Stxs) trigger cellular stress responses, including the ribotoxic stress response and unfolded protein response (UPR), by damaging ribosomes. Understanding these pathways is key to developing therapies against Stx-producing bacterial infections.

Area of Science:

  • Microbiology
  • Cellular Biology
  • Toxicology

Background:

  • Shiga toxin-producing bacteria cause severe diarrheal illness and systemic complications.
  • Shiga toxins (Stxs) are ribosome-inactivating proteins crucial for bacterial virulence.
  • Stxs inhibit protein synthesis by cleaving 28S rRNA.

Purpose of the Study:

  • To characterize the stress-associated signaling pathways activated by Shiga toxins (Stxs) in mammalian cells.
  • To elucidate the mechanisms linking ribosomal damage to downstream cellular responses.
  • To identify potential therapeutic targets for Stx-induced cellular damage.

Main Methods:

  • Investigated the activation of the ribotoxic stress response and unfolded protein response (UPR) by Stxs.
  • Examined the role of MAPK signaling cascades in mediating cellular responses to Stxs.
  • Assessed the activation of ER membrane-localized UPR sensors.

Main Results:

  • Stxs activate both the ribotoxic stress response and the unfolded protein response (UPR).
  • Ribotoxic stress response activation involves depurination of 28S rRNA and signaling through MAPK cascades.
  • Stxs activate all ER membrane-localized UPR sensors, potentially leading to apoptosis.

Conclusions:

  • Stx-induced ribosomal damage triggers distinct stress responses, including ribotoxic stress and UPR.
  • MAPK signaling pathways are critical for innate immunity and apoptosis regulation following Stx intoxication.
  • Characterizing these stress responses offers targets for therapeutic interventions against Stx-mediated diseases.

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