The signaling pathways underlying starvation-induced upregulation of α-mannosidase Ams1 in Saccharomyces cerevisiae
The signaling pathways underlying starvation-induced upregulation of α-mannosidase Ams1 in Saccharomyces cerevisiae
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酿酒酵母饥饿诱导的 α-甘露糖苷酶 Ams1 上调的信号通路
DOI：
10.1016/j.bbagen.2016.02.018
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Wakayama M.
中科院分区：
文献类型：
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作者：
Umekawa M;Ujihara M;Makishima K;Yamamoto S;Takematsu H;Wakayama M.
背景细胞已经进化出了在环境中营养缺乏的情况下生存的机制。在酿酒酵母中，已知α-甘露糖苷酶Ams 1在胞质溶胶中N-连接游离寡糖的催化中起作用。尽管这种酶也被认为可以通过自噬选择性地从胞质溶胶转运到液泡，但这种转运的生理意义尚未阐明。方法为了阐明Ams 1活性的调节机制，我们评估了野生型和各种基因破坏剂在不同营养条件下的无细胞提取物的酶活性。此外，在转录和翻译后的调节Ams 1 examined.ResultsThe活动的Ams 1显着增加后，在培养基中的葡萄糖耗尽。有趣的是，酶的活性也受到氮饥饿的刺激。我们的数据表明，Ams 1的活性是由应激反应转录因子Msn 2/4通过蛋白激酶A和雷帕霉素复合物1的目标途径调节。此外，Ams 1是后饥饿激活的Pep 4依赖的加工vacuoles.ConclusionYeast细胞监测细胞外营养调节甘露糖苷分解代谢通过细胞信号转导pathway.General Significance这项研究表明，细胞内Ams 1活性是精致上调响应营养饥饿诱导表达以及Pep 4依赖的增强活性的液泡。负责调节Ams 1的信号分子也被阐明。
BackgroundCells have evolved the mechanisms to survive nutritional shortages in the environment. InSaccharomyces cerevisiae, α-mannosidase Ams1 is known to play a role in catabolism ofN-linked free oligosaccharides in the cytosol. Although, this enzyme is also known to be transported selectively from the cytosol to the vacuoles by autophagy, the physiological significance of this transport has not been clarified.MethodsTo elucidate the regulatory mechanism of the activity of Ams1, we assessed the enzymatic activity of the cell free extract of the wild-type and various gene disruptants under different nutritional conditions. In addition, the regulation of Ams1 at both transcription and post-translation was examined.ResultsThe activity of Ams1 was significantly increased upon the depletion of glucose in the medium. Interestingly, the activity of the enzyme was also stimulated by nitrogen starvation. Our data showed that the activity of Ams1 is regulated by the stress responsive transcriptional factors Msn2/4 through the protein kinase A and the target of rapamycin complex 1 pathways. In addition, Ams1 is post-translationally activated by Pep4-dependent processing in the vacuoles.ConclusionYeast cells monitor extracellular nutrients to regulate mannoside catabolismviathe cellular signaling pathway.General significanceThis study revealed that intracellular Ams1 activity is exquisitely upregulated in response to nutrient starvation by induced expression as well as by Pep4-dependent enhanced activity in the vacuoles. The signaling molecules responsible for regulation of Ams1 were also clarified.