A novel eukaryotic factor for cytosolic Fe-S cluster assembly
A novel eukaryotic factor for cytosolic Fe-S cluster assembly
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DOI：
10.1093/emboj/cdg455
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发表时间：
2003-09-15
期刊：
影响因子：
11.4
通讯作者：
Walden, WE
中科院分区：
文献类型：
--
作者：
Roy, A;Solodovnikova, N;Walden, WE
铁调节蛋白1 （IRP1）通过[4Fe-4S]簇的组装/拆卸进行调节，该簇将IRP1与胞质乌头化酶相互转化。对携带IRP1转化为c-aconitase所需基因突变的酿酒酵母菌株进行遗传筛选，鉴定出一个以前未被鉴定的必需基因，我们称之为CFD1 ((c)在bar - s簇下（F)在bar - s簇下(d)在bar - efficient）。CFD1编码一个高度保守的p环atp酶。在IRP1转化的酵母中，CFD1 （CFD1 -1）的非致死性突变使c-aconitase特异性活性降低了90%，尽管这些细胞中的IRP1在体外与铁单独孵育后可以很容易地转化为c-aconitase。irp1转化的cfd1-1酵母在c-aconitase中缺乏epr可检测的Fe-S簇，这表明Fe-S簇组装存在缺陷。在cfd1-1酵母中，另一种胞质Fe-S蛋白Leu1p的特异性活性也被>抑制了90%，而线粒体Fe-S蛋白的活性未被抑制。与细胞质活性位点一致，Cfd1p定位于细胞质中。据我们所知，Cfd1p是真核生物中第一个描述的细胞质Fe-S簇组装因子。
Iron regulatory protein 1 (IRP1) is regulated through the assembly/disassembly of a [4Fe-4S] cluster, which interconverts IRP1 with cytosolic aconitase. A genetic screen to isolate Saccharomyces cerevisiae strains bearing mutations in genes required for the conversion of IRP1 to c-aconitase led to the identification of a previously uncharacterized, essential gene, which we call CFD1 ((c) under bar ytosolic (F) under bare-S cluster (d) under bar eficient). CFD1 encodes a highly conserved, putative P-loop ATPase. A non-lethal mutation of CFD1 (cfd1-1) reduced c-aconitase specific activity in IRP1-transformed yeast by >90%, although IRP1 in these cells could be readily converted to c-aconitase in vitro upon incubation with iron alone. IRP1-transformed cfd1-1 yeast lacked EPR-detectable Fe-S clusters in c-aconitase, pointing to a defect in Fe-S cluster assembly. The specific activity of another cytosolic Fe-S protein, Leu1p, was also inhibited by >90% in cfd1-1 yeast, whereas activity of mitochondrial Fe-S proteins was not inhibited. Consistent with a cytosolic site of activity, Cfd1p was localized in the cytoplasm. To our knowledge, Cfd1p is the first cytoplasmic Fe-S cluster assembly factor described in eukaryotes.