Loss of D fg5 glycosylphosphatidylinositol‐anchored membrane protein confers enhanced heat tolerance in S accharomyces cerevisiae

Abstract

Summary The protein product of S accharomyces cerevisiae DFG 5 gene is a glycosylphosphatidylinositol ( GPI )‐anchored plasma membrane protein and a putative glycosidase/glycosyltransferase that links other GPI ‐anchored proteins to β‐glucans in the cell wall. Upon exposure to heat (41°C), DFG 5 deletion mutant dfg5 Δ displayed significantly enhanced heat tolerance as well as lowered level of reactive oxygen species and decreased membrane permeability compared with those in the control ( BY 4741). Comparative transcriptome profiles of BY 4741 and dfg5 Δ revealed that 38 and 23 genes were up‐ and down‐regulated in dfg5 Δ respectively. Of the 23 down‐regulated genes, 11 of 13 viable deletion mutants were identified to be tolerant to heat, suggesting that the down‐regulation of those genes might have contributed to the enhanced heat tolerance in dfg5 Δ. Deletion of DFG 5 caused slight activation of mitogen‐activated protein kinases H og1 in the high‐osmolarity glycerol pathway and S lt2 in the cell wall integrity pathway. Therefore, a model is proposed on the signal transduction pathways associated with deletion of DFG 5 upon heat stress.

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