The sequential activation of the yeast HOG and SLT2 pathways is required for cell survival to cell wall stress
The sequential activation of the yeast HOG and SLT2 pathways is required for cell survival to cell wall stress
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DOI：
10.1091/mbc.e07-08-0742
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发表时间：
2008-03-01
影响因子：
3.3
通讯作者：
Arroyo, Javier
中科院分区：
文献类型：
--
作者：
Bermejo, Clara;Rodriguez, Estefania;Arroyo, Javier
酵母丝裂原活化蛋白激酶（MAPK）信号通路非常精确地将外界刺激转化为细胞反应。MAPKs Slt 2/Mpk 1和Hog 1分别调节细胞壁和渗透胁迫适应的转录应答。出乎意料的是，我们观察到细胞壁完整性（CWI）对由酶切酶（β-1，3葡聚糖酶）引起的细胞壁损伤的响应的激活需要HOG和SLT 2途径两者。在这些条件下，酶解酶激活MAPKs和Slt 2激活取决于HOG途径的Sho 1分支。此外，对酶的适应需要CWI途径的基本组分，即冗余MAPKKs Mkk 1/Mkk 2、MAPKKK Bck 1和Pkc 1，但它不需要上游元件，包括该途径的传感器和鸟嘌呤核苷酸交换因子。此外，参与适应细胞壁胁迫的基因（如CRH 1）的转录激活依赖于Slt 2调控的转录因子Rlm 1，而不依赖于Hog 1调控的转录因子。与这些发现相一致，这两种MAPK途径对于在这些情况下的细胞存活都是必不可少的，因为两种途径的不同组分缺陷的突变株对酶切酶过敏。因此，细胞对细胞壁损伤的适应需要两个MAPK途径的顺序激活。
Yeast mitogen-activated protein kinase (MAPK) signaling pathways transduce external stimuli into cellular responses very precisely. The MAPKs Slt2/Mpk1 and Hog1 regulate transcriptional responses of adaptation to cell wall and osmotic stresses, respectively. Unexpectedly, we observe that the activation of a cell wall integrity (CWI) response to the cell wall damage caused by zymolyase (beta-1,3 glucanase) requires both the HOG and SLT2 pathways. Zymolyase activates both MAPKs and Slt2 activation depends on the Sho1 branch of the HOG pathway under these conditions. Moreover, adaptation to zymolyase requires essential components of the CWI pathway, namely the redundant MAPKKs Mkk1/Mkk2, the MAPKKK Bck1, and Pkc1, but it does not require upstream elements, including the sensors and the guanine nucleotide exchange factors of this pathway. In addition, the transcriptional activation of genes involved in adaptation to cell wall stress, like CRH1, depends on the transcriptional factor Rlm1 regulated by Slt2, but not on the transcription factors regulated by Hog1. Consistent with these findings, both MAPK pathways are essential for cell survival under these circumstances because mutant strains deficient in different components of both pathways are hypersensitive to zymolyase. Thus, a sequential activation of two MAPK pathways is required for cellular adaptation to cell wall damage.