The trehalose protective mechanism during thermal stress in Saccharomyces cerevisiae: the roles of Ath1 and Agt1

FEMS Yeast Res. 2018 Sep 1;18(6). doi: 10.1093/femsyr/foy066.


Trehalose on both sides of the bilayer is a requirement for full protection of membranes against stress. It was not known yet how trehalose, synthesized in the cytosol when dividing Saccharomyces cerevisiae cells are shifted from 28°C to 40°C, is transported to the outside and degraded when cells return to 28°C. According to our results, the lack of Agt1, a trehalose transporter, although had not affected trehalose synthesis, reduced cell tolerance to 51°C and increased lipid peroxidation. The damage was reversed when external trehalose was added during 40°C adaptation, confirming that the reason for the agt1Δ sensitivity is the absence of trehalose at the outside of the lipid bilayer. The 40-28°C condition caused cytosolic trehalase (Nth1) activation, reducing intracellular trehalose and, consequently, the survival rates after 51°C. Although lower than nth1Δ strain, cells deficient in acid trehalase (ath1Δ) maintained increased trehalose levels after 40°C-28°C shift, which conferred protection against 51°C. Both Ath1 and Agt1 were found into vesicles near to plasma membrane in response to stress. This suggests that Agt1 containing vesicles would fuse with the membrane under 40°C to transport part of the cytosolic trehalose to the outside. By a similar mechanism, Ath1 would reach the cell surface to hydrolyze the external trehalose but only when the stress would be over. Corroborating this conclusion, Ath1 activity in soluble cell-free extracts increased after 40°C adaptation but decreased when cells returned to 28°C. During 40°C, Ath1 is confined into vesicles, avoiding the cleavage of the outside trehalose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Transport
  • Cell Membrane / metabolism
  • Cytoplasmic Vesicles / metabolism
  • Heat-Shock Response* / drug effects
  • Lipid Peroxidation / drug effects
  • Monosaccharide Transport Proteins / genetics
  • Monosaccharide Transport Proteins / metabolism*
  • Mutation
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae / physiology*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Symporters / genetics
  • Symporters / metabolism*
  • Trehalase / genetics
  • Trehalase / metabolism*
  • Trehalose / metabolism*
  • Trehalose / pharmacology


  • Monosaccharide Transport Proteins
  • Saccharomyces cerevisiae Proteins
  • Symporters
  • maltose transport system, S cerevisiae
  • Trehalose
  • ATH1 protein, S cerevisiae
  • NTH1 protein, S cerevisiae
  • Trehalase