Tachibana C, Stevens T H
Institute of Molecular Biology, University of Oregon, Eugene 97403.
Mol Cell Biol. 1992 Oct;12(10):4601-11. doi: 10.1128/mcb.12.10.4601-4611.1992.
The product of the EUG1 gene of Saccharomyces cerevisiae is a soluble endoplasmic reticulum protein with homology to both the mammalian protein disulfide isomerase (PDI) and the yeast PDI homolog encoded by the essential PDI1 gene. Deletion or overexpression of EUG1 causes no growth defects under a variety of conditions. EUG1 mRNA and protein levels are dramatically increased in response to the accumulation of native or unglycosylated proteins in the endoplasmic reticulum. Overexpression of the EUG1 gene allows yeast cells to grow in the absence of the PDI1 gene product. Depletion of the PDI1 protein in Saccharomyces cerevisiae causes a soluble vacuolar glycoprotein to accumulate in its endoplasmic reticulum form, and this phenotype is only partially relieved by the overexpression of EUG1. Taken together, our results indicate that PDI1 and EUG1 encode functionally related proteins that are likely to be involved in interacting with nascent polypeptides in the yeast endoplasmic reticulum.
酿酒酵母EUG1基因的产物是一种可溶性内质网蛋白，与哺乳动物蛋白二硫键异构酶（PDI）以及由必需的PDI1基因编码的酵母PDI同源物均具有同源性。在多种条件下，EUG1的缺失或过表达均不会导致生长缺陷。内质网中天然或未糖基化蛋白的积累会显著增加EUG1的mRNA和蛋白质水平。EUG1基因的过表达使酵母细胞能够在没有PDI1基因产物的情况下生长。酿酒酵母中PDI1蛋白的缺失会导致一种可溶性液泡糖蛋白以内质网形式积累，而EUG1的过表达只能部分缓解这种表型。综上所述，我们的结果表明，PDI1和EUG1编码功能相关的蛋白质，它们可能参与在酵母内质网中与新生多肽的相互作用。
