镉胁迫下蛋白磷酸酯酶Msg5对MAPK蛋白激酶Slt2的调控

镉离子(Cd2+)是一种对人体具有致癌性的非必需金属离子,能严重影响生物体的生长、发育和生殖。有丝分裂原蛋白激酶(Mitogen-activated protein kinase,MAPK)是调节细胞存活、增殖和分化中的重要信号分子。细胞壁完整性(Cell Wall Integrity,CWI)途径是酿酒酵母细胞(Saccharomyces cerevisiae)中的一个MAPK信号传导途径,参与镉胁迫下的细胞应答。镉胁迫导致CWI途径的MAPK蛋白激酶Slt2激活并被磷酸化。在CWI途径中,有4个蛋白磷酸酯酶Ptp2、Ptp3、Sdp1和Msg5可以调控Slt2的磷酸化和活性,但是它们在镉胁迫条件下的功能未知。本研究通过同源重组的原理构建了4个单基因缺失株之间的6个双基因缺失株,利用倍比稀释方法分析了这四个磷酸酯酶基因之间在镉胁迫条件下的遗传相互作用。结果发现Msg5是镉胁迫条件下调控Slt2的主要蛋白磷酸酯酶。

Regulation of MAPK Protein Kinase Slt2 by Protein Phosphatase Msg5 under Cadmium Coercion

Cadmium ion is an inessential metal ion for human body, yet oncogenic. It could seriously affect the growth, development and reproduction of organisms. Mitogen activate protein kinases (MAPKs) are important signaling molecules regulating cell survival, proliferation and differentiation. The cell wall integrity (CWI) pathway is one of the MAPK signaling pathways in Saccharomyces cerevisiae, and is involved in the response to cadmium stress. Cadmium stress activates the CWI_MAPK SLT2 and leads to its phosphorylation. There are four protein phosphatases Ptp2, Ptp3, Sdp1 and Msg5 that regulate the phosphorylation of Slt2. However, their functions in cadmium stress are unknown. In this study, six double gene deletion strains between these four protein phosphatase genes were constructed, and analyzed their genetic interactions in the response to cadmium stress. The data indicated that Msg5 is the major protein phosphatase in the regulation of Slt2 under cadmium stress.