Yeast Cell Death Caused by Mutation of the OST2 Gene Encoding the ε-Subunit of Saccharomyces cerevisiae Oligosaccharyltransferase
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An essential ε-subunit of oligosaccharyltransferase Ost2 is a yeast homolog of mammalian highly conserved DAD1 (defender against apoptotic death). In hamster cells, the Gly38Arg mutation in DAD1 causes apoptosis at restrictive temperatures due to a defect in N-linked glycosylation. To analyze the function of Ost2 in yeast cell death, we constructed <I>Saccharomyces cerevisiae</I> strains expressing Gly58Arg (corresponding to the Gly38Arg mutation in hamster DAD1), Gly86Arg, and Glu113Val mutant Ost2. At elevated temperatures, <I>ost2</I> mutants arrested growth by decreasing cell viability. Phosphatidylserine exposure, a phenotypic marker of apoptosis in mammalian cells, was found in <I>ost2</I> mutant cells at 37 °C, although DNA fragmentation was not clearly detected. A high concentration of sorbitol compensates for the temperature sensitivity of the <I>ost2</I> mutant. These results suggest that apoptosis-like cell death in <I>ost2</I> mutants is caused by the secondary effect of overall reduced protein N-linked glycosylation.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(5), 1234-1241, 2006-05-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry