Cyclosporin A but not FK506 activates the integrated stress response in human cells

Anthony O. Fedele, Valérie Carraro, Jianling Xie, Julien Averous, Christopher G. Proud

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3 Citations (Scopus)


Cyclosporin A (CsA) and tacrolimus (FK506) are valuable immunosuppressants for a range of clinical settings, including (but not limited to) organ transplantation and the treatment of autoimmune diseases. They function by inhibiting the activity of the Ca21/calmodulin-dependent phosphatase calcineurin toward nuclear factor of activated T-cells (NF-AT) in T-lymphocytes. However, use of CsA is associated with more serious side effects and worse clinical outcomes than FK506. Here we show that CsA, but not FK506, causes activation of the integrated stress response (ISR), an event which is normally an acute reaction to various types of intracellular insults, such as nutrient deficiency or endoplasmic reticulum stress. These effects of CsA involve at least two of the stress-activated protein kinases (GCN2 and PERK) that act on the translational machinery to slow down protein synthesis via phosphorylation of the eukaryotic initiation factor (eIF) 2a and thereby induce the ISR. These actions of CsA likely contribute to the adverse effects associated with its clinical application.

Original languageEnglish
Pages (from-to)15134-15143
Number of pages10
JournalJournal of Biological Chemistry
Issue number44
Publication statusPublished or Issued - 30 Oct 2020

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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