Tomato QM-Like protein protects Saccharomyces cerevisiae cells against oxidative stress by regulating intracellular proline levels
Tomato QM-Like protein protects Saccharomyces cerevisiae cells against oxidative stress by regulating intracellular proline levels
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DOI：
10.1128/aem.02428-05
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发表时间：
2006-06-01
影响因子：
4.4
通讯作者：
Dickman, Martin B.
中科院分区：
文献类型：
--
作者：
Chen, Changbin;Wanduragala, Srimevan;Dickman, Martin B.
外源脯氨酸可以保护酿酒酵母细胞免受氧化应激的伤害。我们通过过表达酿酒酵母的脯氨酸脱氢酶基因(PUT1)来改变细胞内的脯氨酸水平。Put1p在酿酒酵母中进行了降解脯氨酸的第一步酶促反应。过度表达Put1p会导致低水平的脯氨酸和对过氧化氢和百草枯等氧化剂的过敏性。Put1p活性缺失的put1中断酵母突变体增强了对氧化应激的保护作用，并增加了脯氨酸水平。在酵母中进行条件生死筛选后，我们鉴定了一个编码类QM蛋白(TQM)的番茄基因，并发现TQM在Put1p过表达菌株中的稳定表达可以保护其免受过氧化氢、百草枯和高温的氧化损伤。这种保护作用与活性氧(ROS)减少和脯氨酸积累增加有关。酵母双杂交系统分析表明，TQM在酵母中与Put1p发生物理相互作用，表明TQM直接参与调节脯氨酸水平。TQM还可以通过抑制ROS的生成，将酵母从哺乳动物促凋亡蛋白Bax介导的致死状态中解救出来。我们的结果表明，TQM是多种胁迫反应途径的组成部分，可能在植物的Pro介导的逆境耐受性中发挥作用。
Exogenous proline can protect cells of Saccharomyces cerevisiae from oxidative stress. We altered intracellular proline levels by overexpressing the proline dehydrogenase gene (PUT1) of S. cerevisiae. Put1p performs the first enzymatic step of proline degradation in S. cerevisiae. Overexpression of Put1p results in low proline levels and hypersensitivity to oxidants, such as hydrogen peroxide and paraquat. A put1-disrupted yeast mutant deficient in Put1p activity has increased protection from oxidative stress and increased proline levels. Following a conditional life/death screen in yeast, we identified a tomato (Lycopersicon esculentum) gene encoding a QM-like protein (tQM) and found that stable expression of tQM in the Put1p-overexpressing strain conferred protection against oxidative damage from H2O2, paraquat, and heat. This protection was correlated with reactive oxygen species (ROS) reduction and increased proline accumulation. A yeast two-hybrid system assay was used to show that tQM physically interacts with Put1p in yeast, suggesting that tQM is directly involved in modulating proline levels. tQM also can rescue yeast from the lethality mediated by the mammalian proapoptotic protein Bax, through the inhibition of ROS generation. Our results suggest that tQM is a component of various stress response pathways and may function in proline-mediated stress tolerance in plants.