Biogenesis of iron-sulfur proteins in eukaryotes: a novel task of mitochondria that is inherited from bacteria.

Fe/S clusters are co-factors of numerous proteins with important functions in metabolism, electron transport and regulation of gene expression. Presumably, Fe/S proteins have occurred early in evolution and are present in cells of virtually all species. Biosynthesis of these proteins is a complex process involving numerous components. In mitochondria, this process is accomplished by the so-called ISC (iron-sulfur cluster assembly) machinery which is derived from the bacterial ancestor of the organelles and is conserved from lower to higher eukaryotes. The mitochondrial ISC machinery is responsible for biogenesis iron-sulfur proteins both within and outside the organelle. Maturation of the latter proteins involves the ABC transporter Atm1p which presumably exports iron-sulfur clusters from the organelle. This review summarizes recent developments in our understanding of the biogenesis of iron-sulfur proteins both within bacteria and eukaryotes.