Effects of endoplasmic reticulum stress on the regulation of the lifespan and autophagy of Saccharomyces cerevisiae by PMT1

Abstract:

[Objective] To study the effects of endoplasmic reticulum stress on the regulation of the lifespan and autophagy of Saccharomyces cerevisiae by the protein O-mannosyltransferase 1 (PMT1). [Methods] The double deletion strain (pho8Δ60 pmt1Δ) was constructed based on the genetic homologous recombination. The daughter cells produced by the mother cell of the PMT1-deleted yeast strain (pmt1Δ) treated with tunicamycin (inducing endoplasmic reticulum stress) were counted under a light microscope, and the replicative lifespan of the strain was examined. A microplate reader was used to measure the alkaline phosphatase activity of the pho8Δ60 pmt1Δ strain in the SD-N medium (for inducing autophagy). Western blotting was employed to determine the expression level of the autophagy marker Atg8 in the presence of tunicamycin. The transcript levels of autophagy-related genes ATG1 and ATG8 in the pmt1Δ strain treated with tunicamycin were determined by RT-qPCR. [Results] The replicative lifespan of the pmt1Δ strain was shortened by 38.7%, while the alkaline phosphatase activity of pmt1Δ strain was increased compared with those of the wild type in the presence of tunicamycin. The expression levels of GFP-Atg8 fusion protein and free GFP in the pmt1Δ strain were up-regulated with the increase in the concentration of tunicamycin. The transcript levels of ATG1 and ATG8 were up-regulated in the pmt1Δ strain treated with tunicamycin. [Conclusion] Endoplasmic reticulum stress impairs the replicative lifespan and enhances the autophagy of PMT1-deleted yeast cells.