Redox requirements for ubiquitin-like urmylation of Ahp1, a 2-Cys peroxiredoxin from yeast
Redox requirements for ubiquitin-like urmylation of Ahp1, a 2-Cys peroxiredoxin from yeast
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DOI：
10.1016/j.redox.2020.101438
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发表时间：
2020-02-01
期刊：
影响因子：
11.4
通讯作者：
Schaffrath, Raffael
中科院分区：
文献类型：
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作者：
Brachmann, Cindy;Kaduhr, Lars;Schaffrath, Raffael
酵母peroxiredoxin Ahp1，像其他物种中的相关抗氧化酶一样，经历urmylation，一种与泛素样修饰剂Urm1的赖氨酸定向缀合。Ahp1组装成一个同型二聚体，通过在过氧化物和解析半胱氨酸之间形成亚基间二硫化物来解毒过氧化物，随后被硫氧还蛋白系统还原。尽管urmylation与氧化应激一致，但尚不清楚这种修饰如何在分子水平上发生以及它是否影响peroxiredoxin活性。在这里，我们报告，硫氧还蛋白突变体减少Ahp1 urmylation在酵母和每个亚基的氧化Ahp1二聚体的修饰Urm1建议耦合urmylation二聚化。因此，不能形成二聚体的Ahp1突变体不能像缺乏过氧化物半胱氨酸的突变体那样被urmylated。此外，Ahp1 urmylation涉及至少两个赖氨酸残基接近催化半胱氨酸，可以防止在酵母细胞暴露于高有机过氧化物浓度。我们的研究结果阐明了氧化还原的要求和关键的Ahp1 urmylation的分子决定因素，从而提供了深入了解氧化防御和Urm1利用细胞之间的潜在联系。
The yeast peroxiredoxin Ahp1, like related anti-oxidant enzymes in other species, undergoes urmylation, a lysine-directed conjugation to ubiquitin-like modifier Urm1. Ahp1 assembles into a homodimer that detoxifies peroxides via forming intersubunit disulfides between peroxidatic and resolving cysteines that are subsequently reduced by the thioredoxin system. Although urmylation coincides with oxidative stress, it is unclear how this modification happens on a molecular level and whether it affects peroxiredoxin activity. Here, we report that thioredoxin mutants decrease Ahp1 urmylation in yeast and each subunit of the oxidized Ahp1 dimer is modified by Urm1 suggesting coupling of urmylation to dimerization. Consistently, Ahp1 mutants unable to form dimers, fail to be urmylated as do mutants that lack the peroxidatic cysteine. Moreover, Ahp1 urmylation involves at least two lysine residues close to the catalytic cysteines and can be prevented in yeast cells exposed to high organic peroxide concentrations. Our results elucidate redox requirements and molecular determinants critical for Ahp1 urmylation, thus providing insights into a potential link between oxidant defense and Urm1 utilization in cells.