Systematic screen for mutants resistant to TORC1 inhibition in fission yeast reveals genes involved in cellular ageing and growth.
Systematic screen for mutants resistant to TORC1 inhibition in fission yeast reveals genes involved in cellular ageing and growth.
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DOI：
10.1242/bio.20147245
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发表时间：
2014-02-15
期刊：
影响因子：
2.4
通讯作者：
Bähler J
中科院分区：
文献类型：
--
作者：
Rallis C;López-Maury L;Georgescu T;Pancaldi V;Bähler J
雷帕霉素复合体的靶标1(TORC1)控制生长，对营养做出反应，促进多种生物体的衰老。裂殖酵母是研究TORC1功能和细胞衰老的有价值的遗传模型系统。在这里，我们利用了雷帕霉素和咖啡因的组合作用，它以一种TORC1依赖的方式抑制分裂酵母的生长。我们筛选了一个缺失文库，该文库包含∼84%的非必需分裂酵母基因，用于耐药突变。这一筛选确定了33个编码功能的基因，如转录、激酶、线粒体呼吸、生物合成、细胞内运输和应激反应。在相应的突变体中，5个突变体的最大时间寿命缩短，21个突变体的最大寿命延长；后15个突变体的寿命没有进一步延长，因此可能是TORC1下游的关键靶点。我们对长寿的sck2突变体进行了额外的功能分析，揭示了Sck 2p激酶在TORC1网络中的功能，并且是正常细胞生长、全球蛋白质翻译和核糖体S6蛋白磷酸化所必需的，这是一种营养依赖的方式。值得注意的是，细胞生长缓慢与所有长寿突变体有关，而抗氧化性与此无关。
Target of rapamycin complex 1 (TORC1), which controls growth in response to nutrients, promotes ageing in multiple organisms. The fission yeast Schizosaccharomyces pombe emerges as a valuable genetic model system to study TORC1 function and cellular ageing. Here we exploited the combinatorial action of rapamycin and caffeine, which inhibit fission yeast growth in a TORC1-dependent manner. We screened a deletion library, comprising ∼84% of all non-essential fission yeast genes, for drug-resistant mutants. This screen identified 33 genes encoding functions such as transcription, kinases, mitochondrial respiration, biosynthesis, intra-cellular trafficking, and stress response. Among the corresponding mutants, 5 showed shortened and 21 showed increased maximal chronological lifespans; 15 of the latter mutants showed no further lifespan increase with rapamycin and might thus represent key targets downstream of TORC1. We pursued the long-lived sck2 mutant with additional functional analyses, revealing that the Sck2p kinase functions within the TORC1 network and is required for normal cell growth, global protein translation, and ribosomal S6 protein phosphorylation in a nutrient-dependent manner. Notably, slow cell growth was associated with all long-lived mutants while oxidative-stress resistance was not.