Role of human mitochondrial Nfs1 in cytosolic iron-sulfur protein biogenesis and iron regulation
Role of human mitochondrial Nfs1 in cytosolic iron-sulfur protein biogenesis and iron regulation
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DOI：
10.1128/mcb.00112-06
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发表时间：
2006-08-01
影响因子：
5.3
通讯作者：
Lill, Roland
中科院分区：
文献类型：
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作者：
Biederbick, Annette;Stehling, Oliver;Lill, Roland
真核生物中铁-硫(Fe/S)蛋白的生物发生是一个涉及20多个组分的复杂过程。到目前为止，功能研究主要是在酿酒酵母中进行的。在这里，我们分析了人类半胱氨酸脱硫酶Nfs1(HuNfs1)在生物发生中作为硫供体的作用。该蛋白主要位于线粒体中，但也有少量存在于胞浆/细胞核中。通过小干扰RNA(SiRNA)方法在HeLa细胞中有效地耗尽huNfs1，导致严重的生长迟缓和显著的线粒体形态变化。线粒体和胞质Fe/S蛋白的活性均显著受损，表明huNfs1在人细胞Fe/S蛋白的生物合成中起着重要作用。小鼠Nfs1(MuNfs1)在huNfs1缺失细胞中的表达将生长和Fe/S蛋白活性恢复到野生型水平，表明小干扰RNA缺失方法的特异性。当没有线粒体前序列的情况下合成muNfs1时，没有观察到生长迟缓的互补。这种线粒体外的muNfs1不支持Fe/S蛋白活性的维持，无论是在胞浆中还是在线粒体中。总之，我们的研究表明，线粒体内必需的huNfs1是细胞内Fe/S蛋白高效成熟所必需的。这一结果对细胞内铁调节蛋白1对铁稳态的调控有一定的意义。
The biogenesis of iron-sulfur (Fe/S) proteins in eukaryotes is a complex process involving more than 20 components. So far, functional investigations have mainly been performed in Saccharomyces cerevisiae. Here, we have analyzed the role of the human cysteine desulfurase Nfs1 (huNfs1), which serves as a sulfur donor in biogenesis. The protein is located predominantly in mitochondria, but small amounts are present in the cytosol/nucleus. huNfs1 was depleted efficiently in HeLa cells by a small interfering RNA (siRNA) approach, resulting in a drastic growth retardation and striking morphological changes of mitochondria. The activities of both mitochondrial and cytosolic Fe/S proteins were strongly impaired, demonstrating that huNfs1 performs an essential function in Fe/S protein biogenesis in human cells. Expression of murine Nfs1 (muNfs1) in huNfs1-depleted cells restored both growth and Fe/S protein activities to wild-type levels, indicating the specificity of the siRNA depletion approach. No complementation of the growth retardation was observed, when muNfs1 was synthesized without its mitochondrial presequence. This extramitochondrial muNfs1 did not support maintenance of Fe/S protein activities, neither in the cytosol nor in mitochondria. In conclusion, our study shows that the essential huNfs1 is required inside mitochondria for efficient maturation of cellular Fe/S proteins. The results have implications for the regulation of iron homeostasis by cytosolic iron regulatory protein 1.