查看文章

The assembly of cytosolic and nuclear iron-sulfur (Fe/S) proteins in yeast is dependent on the iron-sulfur cluster assembly and export machineries in mitochondria and three recently identified extramitochondrial proteins, the P-loop NTPases Cfd1 and Nbp35 and the hydrogenase-like Nar1. However, the molecular mechanism of Fe/S protein assembly in the cytosol is far from being understood, and more components are anticipated to take part in this process. Here, we have identified and functionally characterized a novel WD40 repeat protein, designated Cia1, as an essential component required for Fe/S cluster assembly in vivo on cytosolic and nuclear, but not mitochondrial, Fe/S proteins. Surprisingly, Nbp35 and Nar1, themselves Fe/S proteins, could assemble their Fe/S clusters in the absence of Cia1, demonstrating that these components act before Cia1. Consequently, Cia1 is involved in a late step of Fe/S …