Loss of vacuolar proton-translocating ATPase activity in yeast results in chronic oxidative stress
Loss of vacuolar proton-translocating ATPase activity in yeast results in chronic oxidative stress
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DOI：
10.1074/jbc.m608293200
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发表时间：
2007-03-09
影响因子：
4.8
通讯作者：
Kane, Patricia M.
中科院分区：
文献类型：
--
作者：
Milgrom, Elena;Diab, Heba;Kane, Patricia M.
在最近的基因组筛选中，缺乏液泡质子易位ATPas （V-ATPase）亚基的酵母突变体（vma突变体）对几种不同的氧化剂敏感（Thorpe， G. W. Fong， C. S, Alic， N., Higgins， V. J, and Dawes, 1）。W.（2004）。学会科学。（美国第10卷，第6564 - 6569页）。我们证实，缺乏V亚基（vma2 Delta）、V亚基或两种V亚基亚型中的任何一种的突变体对H2O2非常敏感，并且比野生型细胞对甲氧二酮和二胺更敏感。vma2 Delta突变体即使在没有应用氧化剂的情况下也含有较高水平的活性氧和高水平的氧化蛋白损伤，这表明氧化应激的内源性来源。缺乏线粒体DNA的vma2 Delta突变体既没有改善生长，也没有降低对过氧化物的敏感性，在突变体中排除了呼吸作为内源性活性氧的主要来源。缺乏VAM2和主要细胞质防御系统组分的双突变体对H2O2表现出合成敏感性。微阵列分析比较了野生型和vma2 Delta突变体在pH 5 （vma2 Delta突变体的允许条件）下生长的细胞，发现Aft1/Aft2调控中一些铁摄取和代谢基因的高水平上调。TSA2编码胞质硫氧还蛋白过氧化物酶的一种异构体，它被强烈诱导，但其他氧化应激防御系统未被诱导。结果表明，v - atp酶活性有助于保护细胞免受内源性氧化应激。
Yeast mutants lacking vacuolar proton-translocating ATPas (V-ATPase) subunits (vma mutants) were sensitive to several different oxidants in a recent genomic screen (Thorpe, G. W. Fong, C. S., Alic, N., Higgins, V. J., and Dawes, 1. W. (2004) Proc Natl. Acad. Sci. U. S.A. 10 1, 6564 - 6569). We confirmed that mutants lacking a V, subunit (vma2 Delta), V. subunit, or either of the two V. a subunit isoforms are acutely sensitive to H2O2 and more sensitive to menadione and diamide than wild-type cells The vma2 Delta mutant contains elevated levels of reactive oxygen species and high levels of oxidative protein damage even in the absence of an applied oxidant, suggesting an endogenous source of oxidative stress. vma2 Delta mutants lacking mitochondrial DNA showed neither improved growth nor decreased sensitivity to peroxide, excluding respiration as the major source of the endogenous reactive oxygen species in the mutant. Double mutants lacking both VAM2 and components of the major cytosolic defense systems exhibited synthetic sensitivity to H2O2. Microarray analysis comparing wild-type and vma2 Delta mutant cells grown at pH 5, permissive conditions for the vma2 Delta mutant, indicated high level up-regulation of several iron uptake and metabolism genes that are part of the Aft1/Aft2 regulon. TSA2, which encodes an isoform of the cytosolic thioredoxin peroxidase, was strongly induced, but other oxidative stress defense systems were not induced. The results indicate that V-ATPase activity helps to protect cells from endogenous oxidative stress.