Acute glucose starvation activates the nuclear localization signal of a stress-specific yeast transcription factor
Acute glucose starvation activates the nuclear localization signal of a stress-specific yeast transcription factor
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DOI：
10.1093/emboj/21.1.135
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发表时间：
2002-01-15
期刊：
影响因子：
11.4
通讯作者：
Schüller, C
中科院分区：
文献类型：
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作者：
Görner, W;Durchschlag, E;Schüller, C
在酵母中，环境条件控制转录因子Msn 2，其核积累和功能是营养有效性和环境胁迫负荷的敏感指标。我们发现Msn 2的核定位信号（NLS）是cAMP依赖性蛋白激酶（cAPK）的直接靶点。遗传分析表明，Msn 2-NLS功能被磷酸化抑制，被去磷酸化激活。Msn 2-NLS功能不受通常诱导全长Msn 2的核积累的许多应激条件的影响。然而，Msn 2-NLS磷酸化状态对发酵生长期间的碳水化合物波动高度敏感。去磷酸化发生在葡萄糖戒断后>2分钟，但该效应可通过重新喂食葡萄糖而迅速逆转。这种对葡萄糖消耗的反应是由于cAPK活性的变化，而不是蛋白磷酸酶活性的增加。令人惊讶的是，经典的葡萄糖传感系统并没有连接到这个快速反应系统。我们的研究结果进一步表明，一般的压力信号不会导致cAPK活性的短期抑制。它们通过影响依赖于Msn 5的核输出和/或保留机制对Msn 2起作用。
In yeast, environmental conditions control the transcription factor Msn2, the nuclear accumulation and function of which serve as a sensitive indicator of nutrient availablity and environmental stress load. We show here that the nuclear localization signal (NLS) of Msn2 is a direct target of cAMP-dependent protein kinase (cAPK). Genetic analysis suggests that Msn2-NLS function is inhibited by phosphorylation and activated by dephosphorylation. Msn2-NLS function is unaffected by many stress conditions that normally induce nuclear accumulation of full-length Msn2. The Msn2-NLS phosphorylation status is, however, highly sensitive to carbohydrate fluctuations during fermentative growth. Dephosphorylation occurs in >2 min after glucose withdrawal but the effect is reversed rapidly by refeeding with glucose. This response to glucose depletion is due to changes in cAPK activity rather than an increase in protein phosphatase activity. Surprisingly, the classical glucose-sensing systems are not connected to this rapid response system. Our results further imply that generic stress signals do not cause short-term depressions in cAPK activity. They operate on Msn2 by affecting an Msn5-dependent nuclear export and/or retention mechanism.