A systematic genetic screen for genes involved in sensing inorganic phosphate availability in Saccharomyces cerevisiae.
A systematic genetic screen for genes involved in sensing inorganic phosphate availability in Saccharomyces cerevisiae.
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DOI：
10.1371/journal.pone.0176085
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
O'Shea EK
中科院分区：
文献类型：
--
作者：
Choi J;Rajagopal A;Xu YF;Rabinowitz JD;O'Shea EK
酿酒酵母通过调节磷酸盐响应（PHO）信号通路的活性来响应细胞外无机磷酸盐（Pi）可用性的变化，使细胞能够维持必需营养素Pi的细胞内水平。PI限制诱导由肌醇六磷酸激酶Vip 1合成的肌醇七磷酸（IP7）的上调，触发通过CDK抑制剂Pho 81的Pho 80/Pho 85细胞周期蛋白-细胞周期蛋白依赖性激酶（CDK）复合物的抑制，其通过CDK靶和转录因子Pho 4上调PHO调节子。为了确定参与Pho 80/Pho 85/Pho 81复合物上游信号传导的基因以及它们如何相互作用以调节PHO通路，我们使用合成基因阵列方法进行了全基因组筛选。我们确定了300多个突变体的缺陷信号上游的pho 80/pho 85/pho 81复合物，包括AAH 1，它编码的腺嘌呤脱氨酶，负调控PHO途径中的Vip 1依赖性的方式。此外，我们发现，即使在没有VIP 1的情况下，PHO通路可以在长时间的Pi饥饿下被激活，这表明PHO通路调节机制的复杂性。
Saccharomyces cerevisiae responds to changes in extracellular inorganic phosphate (Pi) availability by regulating the activity of the phosphate-responsive (PHO) signaling pathway, enabling cells to maintain intracellular levels of the essential nutrient Pi. Pi-limitation induces upregulation of inositol heptakisphosphate (IP7) synthesized by the inositol hexakisphosphate kinase Vip1, triggering inhibition of the Pho80/Pho85 cyclin-cyclin dependent kinase (CDK) complex by the CDK inhibitor Pho81, which upregulates the PHO regulon through the CDK target and transcription factor Pho4. To identify genes that are involved in signaling upstream of the Pho80/Pho85/Pho81 complex and how they interact with each other to regulate the PHO pathway, we performed genome-wide screens with the synthetic genetic array method. We identified more than 300 mutants with defects in signaling upstream of the Pho80/Pho85/Pho81 complex, including AAH1, which encodes an adenine deaminase that negatively regulates the PHO pathway in a Vip1-dependent manner. Furthermore, we showed that even in the absence of VIP1, the PHO pathway can be activated under prolonged periods of Pi starvation, suggesting complexity in the mechanisms by which the PHO pathway is regulated.