Thio modification of yeast cytosolic tRNA is an iron-sulfur protein-dependent pathway
Thio modification of yeast cytosolic tRNA is an iron-sulfur protein-dependent pathway
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DOI：
10.1128/mcb.01321-06
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发表时间：
2007-04-01
影响因子：
5.3
通讯作者：
Hayashi, Hideyuki
中科院分区：
文献类型：
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作者：
Nakai, Yumi;Nakai, Masato;Hayashi, Hideyuki
酵母半胱氨酸脱硫酶Nfs1的缺陷导致线粒体tRNAs （mt-tRNAs）和细胞质tRNAs （cy-tRNAs）尿苷的2-硫代修饰严重受损。Nfs1还可以提供由线粒体和细胞质铁/硫团簇组装机制（分别称为ISC和CIA）产生的铁-硫（Fe/S）团簇的硫原子。因此，一个关键问题仍然存在，即Fe/S簇的生物合成是否是酵母细胞两个亚细胞区室中trna的2-硫代修饰的先决条件。为了阐明这个问题，我们询问除了Nfs1外，线粒体ISC和/或细胞质CIA组分是否参与这些trna的2-硫代修饰。我们在这里证明了三种CIA成分Cfd1， Nbp35和Cia1是cy- trna的2硫代修饰所必需的，而不是mt- trna的2硫代修饰。有趣的是，线粒体支架蛋白Isu1和Isu2是cy- trna的2硫代修饰所必需的，而不是mt- trna的2硫代修饰所必需的，而线粒体Nfs1是这两种2硫代修饰所必需的。这些结果清楚地表明，cy- trna的2-硫代修饰是Fe/S蛋白依赖的，因此需要CIA和ISC机制，而mt- trna的2-硫代修饰是Fe/S簇独立的，不需要除Nfs1外的关键线粒体ISC成分。
Defects in the yeast cysteine desulfurase Nfs1 cause a severe impairment in the 2-thio modification of uridine of mitochondrial tRNAs (mt-tRNAs) and cytosolic tRNAs (cy-tRNAs). Nfs1 can also provide the sulfur atoms of the iron-sulfur (Fe/S) clusters generated by the mitochondrial and cytosolic Fe/S cluster assembly machineries, termed ISC and CIA, respectively. Therefore, a key question remains as to whether the biosynthesis of Fe/S clusters is a prerequisite for the 2-thio modification of the tRNAs in both of the subcellular compartments of yeast cells. To elucidate this question, we asked whether mitochondrial ISC and/or cytosolic CIA components besides Nfs1 were involved in the 2-thio modification of these tRNAs. We demonstrate here that the three CIA components, Cfd1, Nbp35, and Cia1, are required for the 2-thio modification of cy-tRNAs but not of mt-tRNAs. Interestingly, the mitochondrial scaffold proteins Isu1 and Isu2 are required for the 2-thio modification of the cy-tRNAs but not of the mt-tRNAs, while mitochondrial Nfs1 is required for both 2-thio modifications. These results clearly indicate that the 2-thio modification of cy-tRNAs is Fe/S protein dependent and thus requires both CIA and ISC machineries but that of mt-tRNAs is Fe/S cluster independent and does not require key mitochondrial ISC components except for Nfs1.