【作者】 郭蜀光；

【导师】 李锁平； Yu Jiang；

【作者基本信息】 河南大学 ， 植物学， 2009， 博士

【摘要】 在酿酒酵母中,鸟苷三磷酸激酶(GTPase)Rho1控制肌动蛋白的极化和细胞壁的扩增。当细胞暴露于各种干扰细胞壁的环境中时,Rho1激活Pkc1和Mpk1从而导致肌动蛋白去极化和细胞壁重塑。Pkc1是哺乳动物蛋白激酶C(PKC)的同源酶;Mpk1属于有丝分裂原激活蛋白激酶( MAPK )。在这项研究中,我们发现一种新的反馈调节机制调控Rho1-Pkc1–MAPK信号传导途径。这一调节机制包括Rom2鸟嘌呤核苷酸交换因子,Rho1和Mpk1。这个Mpk1依赖性的反馈调节机制对于调节Rho1激酶的功能是一个非常重要的步骤。这一反馈机制的激活负责Rom2的重新分配和在胁迫条件下酵母从芽到细胞边缘的细胞壁合成活动。这一反馈调节机制对于终止Rho1在Pkc1 - MAPK途径中的激酶活性、重新极化肌动蛋白细胞骨架和适应胁迫影响后细胞的恢复增长也非常重要。更多还原

【Abstract】 In the yeast Saccharomyces cerevisiae the guanosine triphosphatase (GTPase) Rho1 controls actin polarization and cell wall expansion. When cells are exposed to various environmental stresses that perturb the cell wall, Rho1 activates Pkc1, a mammalian Protein Kinase C homologue, and Mpk1, a mitogen activated protein kinase (MAPK), resulting in actin depolarization and cell wall remodeling. In this study, we demonstrate a novel feedback loop in this Rho1-mediated Pkc1-MAPK pathway that involves regulation of Rom2, the guanine nucleotide exchange factor of Rho1, by Mpk1, the end kinase of the pathway. This previously unrecognized Mpk1-depedent feedback is a critical step in regulating Rho1 function. Activation of this feedback mechanism is responsible for redistribution of Rom2 and cell wall synthesis activity from the bud to cell periphery under stress conditions. It is also required for terminating Rho1 activity toward the Pkc1-MAPK pathway and for repolarizing actin cytoskeleton and restoring growth after the stressed cells become adapted.更多还原