Activation of Gcn2 in response to different stresses

PLoS One. 2017 Aug 3;12(8):e0182143. doi: 10.1371/journal.pone.0182143. eCollection 2017.

Abstract

All organisms have evolved pathways to respond to different forms of cellular stress. The Gcn2 kinase is best known as a regulator of translation initiation in response to starvation for amino acids. Work in budding yeast has showed that the molecular mechanism of GCN2 activation involves the binding of uncharged tRNAs, which results in a conformational change and GCN2 activation. This pathway requires GCN1, which ensures delivery of the uncharged tRNA onto GCN2. However, Gcn2 is activated by a number of other stresses which do not obviously involve accumulation of uncharged tRNAs, raising the question how Gcn2 is activated under these conditions. Here we investigate the requirement for ongoing translation and tRNA binding for Gcn2 activation after different stresses in fission yeast. We find that mutating the tRNA-binding site on Gcn2 or deleting Gcn1 abolishes Gcn2 activation under all the investigated conditions. These results suggest that tRNA binding to Gcn2 is required for Gcn2 activation not only in response to starvation but also after UV irradiation and oxidative stress.

MeSH terms

  • Amino Acid Sequence
  • Cycloheximide / pharmacology
  • Eukaryotic Initiation Factor-2 / metabolism
  • Hydrogen Peroxide / toxicity
  • Mutagenesis
  • Oxidative Stress / drug effects
  • Phosphorylation / drug effects
  • Phosphorylation / radiation effects
  • Protein Biosynthesis / radiation effects
  • Protein Synthesis Inhibitors / pharmacology
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • RNA, Transfer / metabolism*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / metabolism
  • Schizosaccharomyces / radiation effects
  • Schizosaccharomyces pombe Proteins / chemistry
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Sequence Alignment
  • Stress, Physiological / genetics*
  • Ultraviolet Rays

Substances

  • Eukaryotic Initiation Factor-2
  • Protein Synthesis Inhibitors
  • Schizosaccharomyces pombe Proteins
  • RNA, Transfer
  • Cycloheximide
  • Hydrogen Peroxide
  • Gcn2 protein, S pombe
  • Protein-Serine-Threonine Kinases

Grant support

The Norwegian Research Council and the South-Eastern Norwegian Health Authorities supported this work. Róbert Zach was supported by the Erasmus program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.