The oxidative stress response mediated via Pos9/Skn7 is negatively regulated by the Ras PKA pathway in Saccharomyces cerevisiae
The oxidative stress response mediated via Pos9/Skn7 is negatively regulated by the Ras PKA pathway in Saccharomyces cerevisiae
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DOI：
10.1007/s004380050017
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发表时间：
1999-06-01
期刊：
影响因子：
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通讯作者：
Entian, KD
中科院分区：
文献类型：
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作者：
Charizanis, C;Juhnke, H;Entian, KD
将酿酒酵母暴露于高浓度的过氧化氢会诱导参与氧化应激反应的多个基因的转录。两个主要的转录因子 Pos9/Skn7 和 Yap1 参与了这种诱导。 Yap1 或 Pos9/Skn7 与 Ga14 DNA 结合结构域的融合体作为转录因子具有活性。 Gal4-Yap1 依赖性报告基因活性仅受氧化应激的微弱调节。相比之下，Ga14 DNA 结合结构域与 Pos9/Skn7 蛋白的融合产生了一个独立于 YAP1 基因的转录因子，并受到氧化应激的严格调控，表明信号级联影响了 Pos9/Skn7 蛋白。我们观察到 Ras/PKA（cAMP 依赖性蛋白激酶 A）途径影响此信号传导。当 PKA 活性较低（存在多拷贝 PDE2 或 cyr1(D822-->A) 突变）时，即使在没有氧化应激的情况下，也可以观察到最大报告基因活性。相比之下，pde2或bcy1的高PKA活性tin菌株突变体，或表达显性活性Ras2（Val19））导致氧化应激后激活完全丧失。 Ras/PKA 通路突变体中 Pos9/Skn7 靶基因的转录也受到影响。此外，我们证明激活的 Pos9/Skn7 对于 Yap1 依赖性报告基因诱导是必需的。
Exposure of Saccharomyces cerevisiae to elevated concentrations of hydrogen peroxide induces transcription of several genes involved in the oxidative stress response. Two major transcription factors are involved in this induction, Pos9/Skn7 and Yap1. Fusions of either Yap1 or Pos9/Skn7 with the Ga14 DNA binding domain are active as transcription factors. Gal4-Yap1-dependent reporter gene activity is only weakly regulated by oxidative stress. In contrast, fusion of the Ga14 DNA binding domain to the Pos9/Skn7 protein results in a transcription factor that is independent of the YAP1 gene and is strictly regulated by oxidative stress indicating that a signaling cascade impinges on the Pos9/Skn7 protein. We have observed that the Ras/PKA (cAMP-dependent protein kinase A) pathway affects this signaling. When PKA activity was low tin the presence of multicopy PDE2 or a cyr1(D822-->A) mutation) maximum reporter gene activity was observed even in the absence of oxidative stress. In contrast, high PKA activity tin strains mutant for either pde2 or bcy1, or expressing the dominant active Ras2(Val19)) resulted in a complete loss of activation following oxidative stress. The transcription of Pos9/Skn7 target genes was also affected in Ras/PKA pathway mutants. Furthermore, we demonstrated that activated Pos9/Skn7 is necessary for Yap1-dependent reporter gene induction.