A synthetic analysis of the Saccharomyces cerevisiae stress sensor Mid2p, and identification of a Mid2p-interacting protein, Zeo1p, that modulates the PKC1-MPK1 cell integrity pathway
A synthetic analysis of the Saccharomyces cerevisiae stress sensor Mid2p, and identification of a Mid2p-interacting protein, Zeo1p, that modulates the PKC1-MPK1 cell integrity pathway
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DOI：
10.1099/mic.0.26471-0
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发表时间：
2003-09-01
期刊：
影响因子：
2.8
通讯作者：
Bussey, H
中科院分区：
文献类型：
--
作者：
Green, R;Lesage, G;Bussey, H
Mid 2 p是一种质膜蛋白，其在酿酒酵母中作为细胞壁应激的传感器起作用，在暴露于交配信息素、荧光钙白色和热期间经由小GTdR Rho 1 p激活PKC 1-MPK 1细胞完整性途径。为了检查Mid 2 p信号传导，进行了mid 2突变体的全局合成相互作用分析;这鉴定了11个相互作用基因。这些包括WSC 1和ROM 2，细胞完整性途径信号传导的上游元件，以及FKS 1和SMI 1，1，3-β-葡聚糖合成所需。这些合成相互作用表明Wsc 1 p传感器通过Rom 2 p以Mid 2 p独立的方式激活Fks 1 p葡聚糖合酶。为了进一步探索Mid 2 p信号传导，使用Mid 2 p的胞质尾进行双杂交筛选;这鉴定了ZEO 1（YOL 109 w），其编码定位于质膜的12 kDa外周膜蛋白。ZEO 1的破坏导致对荧光钙白色的抗性和Mpk 1 p的Mid 2 p依赖性组成性磷酸化，支持Zeo 1 p在细胞完整性途径中的作用。与此一致，zeo 1缺陷细胞抑制Rho 1 p，GDP-GTP交换因子Rom 2 p突变体的生长缺陷，同时在37 ℃下加剧sac 7 Delta突变体的生长缺陷。相比之下，mid 2Delta突变体具有与zeo 1Delta突变体相反的作用，与rom 2Delta合成致死，并抑制sac 7 Delta的18 ℃生长缺陷，而MID 2的过表达挽救rom 2Delta 37 ℃生长缺陷。因此，MID 2和ZEO 1似乎在酵母PKC 1-MPK 1细胞完整性途径的调节中发挥相互作用。
Mid2p, is a plasma membrane protein that functions in Saccharomyces cerevisiae as a sensor of cell wall stress, activating the PKC1-MPK1 cell integrity pathway via the small GTPase Rho 1 p during exposure to mating pheromone, calcofluor white, and heat. To examine Mid2p signalling, a global synthetic interaction analysis of a mid2 mutant was performed; this identified 11 interacting genes. These include WSC1 and ROM2, upstream elements in cell integrity pathway signalling, and FKS1 and SMI1, required for 1,3-beta-glucan synthesis. These synthetic interactions indicate that the Wsc1p sensor acts through Rom2p to activate the Fks1p glucan synthase in a Mid2p-independent way. To further explore Mid2p signalling a two-hybrid screen was done using the cytoplasmic tail of Mid2p; this identified ZEO1 (YOL109w), encoding a 12 kDa peripheral membrane protein that localizes to the plasma membrane. Disruption of ZEO1 leads to resistance to calcofluor white and to a Mid2p-dependent constitutive phosphorylation of Mpk1p, supporting a role for Zeo1p in the cell integrity pathway. Consistent with this, zeo1-deficient cells suppress the growth defect of mutants in the Rho1p, GDP-GTP exchange factor Rom2p, while exacerbating the growth defect of sac7Delta mutants at 37degreesC. In contrast, mid2Delta mutants have opposing effects to zeo1Delta mutants, being synthetically lethal with rom2Delta, and suppressing an 18 degreesC growth defect of sac7Delta, while overexpression of MID2 rescues a rom2Delta 37 degreesC growth defect. Thus, MID2 and ZEO1 appear to play reciprocal roles in the modulation of the yeast PKC1-MPK1 cell integrity pathway.