An investigation into the proteins responsible for the translational inhibition seen in the yeast Saccharomyces cerevisiae following fusel alcohol exposure

UoM administered thesis: Phd

  • Authors:
  • Jemma Keenan

Abstract

Fusel alcohols signal nitrogen scarcity to elicit a range of responses in the yeast Saccharomyces cerevisiae. These alcohols activate pseudohyphal growth and cause rapid inhibition of translation initiation. Previous work from our lab has highlighted that the translation initiation factor eIF2B is a target for this regulation. eIF2B is the guanine nucleotide exchange factor required for recycling eIF2•GDP to eIF2•GTP. The GTP bound form of eIF2 can interact with the Methionyl initiator tRNA to form the ternary complex. Fusel alcohols target eIF2B leading to reduced ternary complex; however the mechanism by which alcohols cause this effect is currently unknown. This study aims to characterize the effects of fusel alcohols on eIF2B and identify post-translational modifications, which may be responsible for translation inhibition.Following purification of eIF2B, a number of novel phosphorylation sites have been identified using mass spectrometry. In particular, phosphorylated serine has been identified at position 131 within yeast eIF2Bdelta. Phosphoantibody analysis suggests that the phosphorylation status of this residue differs following fusel alcohol treatment. Mutagenesis experiments are consistent with phosphorylation of this residue being essential for the translational inhibition seen following fusel alcohol exposure. Therefore, phosphorylation of this residue may prime eIF2B for regulation and provide a switch to sensitize the process of translation to particular conditions.

Details

Original languageEnglish
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Award date31 Dec 2013