Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
Institute of Bioengineering, School of Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.
Sci Rep. 2020 Sep 24;10(1):15613. doi: 10.1038/s41598-020-72391-y.
Control of the protein phosphorylation status is a major mechanism for regulation of cellular processes, and its alteration often lead to functional disorders. Ppz1, a protein phosphatase only found in fungi, is the most toxic protein when overexpressed in Saccharomyces cerevisiae. To investigate the molecular basis of this phenomenon, we carried out combined genome-wide transcriptomic and phosphoproteomic analyses. We have found that Ppz1 overexpression causes major changes in gene expression, affecting ~ 20% of the genome, together with oxidative stress and increase in total adenylate pools. Concurrently, we observe changes in the phosphorylation pattern of near 400 proteins (mainly dephosphorylated), including many proteins involved in mitotic cell cycle and bud emergence, rapid dephosphorylation of Snf1 and its downstream transcription factor Mig1, and phosphorylation of Hog1 and its downstream transcription factor Sko1. Deletion of HOG1 attenuates the growth defect of Ppz1-overexpressing cells, while that of SKO1 aggravates it. Our results demonstrate that Ppz1 overexpression has a widespread impact in the yeast cells and reveals new aspects of the regulation of the cell cycle.
蛋白质磷酸化状态的控制是调节细胞过程的主要机制，其改变通常会导致功能障碍。Ppz1 是一种仅存在于真菌中的蛋白磷酸酶，在酿酒酵母中过表达时是毒性最强的蛋白质。为了研究这一现象的分子基础，我们进行了全基因组转录组学和磷酸化蛋白质组学联合分析。我们发现 Ppz1 过表达导致基因表达的重大变化，影响了基因组的约 20%，同时还伴有氧化应激和总腺苷酸池的增加。同时，我们观察到近 400 种蛋白质（主要是去磷酸化）的磷酸化模式发生变化，其中包括许多参与有丝分裂细胞周期和芽出芽的蛋白质，Snf1 及其下游转录因子 Mig1 的快速去磷酸化，以及 Hog1 和其下游转录因子 Sko1 的磷酸化。HOG1 的缺失减弱了 Ppz1 过表达细胞的生长缺陷，而 SKO1 的缺失则加剧了这种缺陷。我们的结果表明，Ppz1 过表达对酵母细胞有广泛的影响，并揭示了细胞周期调控的新方面。
