Yapsins are a family of aspartyl proteases required for cell wall integrity in Saccharomyces cerevisiae
Yapsins are a family of aspartyl proteases required for cell wall integrity in Saccharomyces cerevisiae
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DOI：
10.1128/ec.4.8.1364-1374.2005
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发表时间：
2005-08-01
期刊：
影响因子：
--
通讯作者：
Fuller, RS
中科院分区：
文献类型：
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作者：
Krysan, DJ;Ting, EL;Fuller, RS
酵母细胞壁是一种重要的细胞外细胞器，可保护细胞在环境应激和形态发生过程中免于裂解。在这里，我们证明了 yapsin 家族的五种糖基磷脂酰肌醇连接的天冬氨酰蛋白酶是酿酒酵母细胞壁完整性所必需的。 Yapsin 无效突变体对细胞壁扰动表现出超敏感性，并且 yps1 Delta 2 Delta 突变体和五重 yapsin 突变体 (5yps Delta) 在 37°C 下都会经历渗透介质细胞裂解。5yps Delta 和 yps1 Delta 2 Delta 突变体的细胞壁中 1,3- 和 1,6-β-葡聚糖的量减少。尽管5yps Delta突变体体内1,3-和1,6-β-葡聚糖的掺入减少，但1,3-和1,6-β-葡聚糖合成的体外比活性与野生型相似，表明yapsin影响葡聚糖合成的下游过程，并且yapsin可能参与细胞壁葡聚糖的掺入或保留。据推测，作为对细胞壁组成显着变化的反应，细胞壁完整性丝裂原激活激酶信号级联（PKC1-MPK 途径）在 5 yps Delta 中基本活跃。 YPS1 表达在细胞壁应激和重塑过程中以 PKC1-MPK1 依赖性方式诱导，表明 Yps1p 是细胞壁完整性反应的直接且重要的输出。 YPS1 的白色念珠菌 (SAP9) 和光滑念珠菌 (CgYPS1) 同源物补充了 yps1 Delta 突变体的表型。总而言之，这些数据表明，yapsin 在酿酒酵母的葡聚糖稳态中发挥重要作用，并且yapsin 同源物可能在致病性酵母白色念珠菌和光滑念珠菌中发挥类似的作用。
The yeast cell wall is a crucial extracellular organelle that protects the cell from lysis during environmental stress and morphogenesis. Here, we demonstrate that the yapsin family of five glycosylphosphatidylinositol-linked aspartyl proteases is required for cell wall integrity in Saccharomyces cerevisiae. Yapsin null mutants show hypersensitivity to cell wall perturbation, and both the yps1 Delta 2 Delta mutant and the quintuple yapsin mutant (5yps Delta) undergo osmoremedial cell lysis at 37 degrees C. The cell walls of both 5yps Delta and yps1 Delta 2 Delta mutants have decreased amounts of 1,3- and 1,6-beta-glucan. Although there is decreased incorporation of both 1,3- and 1,6-beta-glucan in the 5yps Delta mutant in vivo, in vitro specific activity of both 1,3- and 1,6-beta-glucan synthesis is similar to wild type, indicating that the yapsins affect processes downstream of glucan synthesis and that the yapsins may be involved in the incorporation or retention of cell wall glucan. Presumably as a response to the significant alterations in cell wall composition, the cell wall integrity mitogen-activated kinase signaling cascade (PKC1-MPK pathway) is basally active in 5yps Delta. YPS1 expression is induced during cell wall stress and remodeling in a PKC1-MPK1-dependent manner, indicating that Yps1p is a direct, and important, output of the cell wall integrity response. The Candida albicans (SAP9) and Candida glabrata (CgYPS1) homologues of YPS1 complement the phenotypes of the yps1 Delta mutant. Taken together, these data indicate that the yapsins play an important role in glucan homeostasis in S. cerevisiae and that yapsin homologues may play a similar role in the pathogenic yeasts C. albicans and C. glabrata.