The essential role of mitochondria in the biogenesis of cellular iron-sulfur proteins.
Iron-sulfur (Fe/S) proteins play an important role in electron transfer processes and in various enzymatic reactions. In eukaryotic cells, known Fe/S proteins are localised in mitochondria, the cytosol and the nucleus. The biogenesis of these proteins has only recently become the focus of investigations. Mitochondria are the major site of Fe/S cluster biosynthesis in the cell. The organelles contain an Fe/S cluster biosynthesis apparatus that resembles that of prokaryotic cells. This apparatus consists of some ten proteins including a cysteine desulfurase producing elemental sulfur for biogenesis, a ferredoxin involved in reduction, and two chaperones. The mitochondrial Fe/S cluster synthesis apparatus not only assembles mitochondrial Fe/S proteins, but also initiates formation of extra-mitochondrial Fe/S proteins. This involves the export of sulfur and possibly iron from mitochondria to the cytosol, a reaction performed by the ABC transporter Atm1p of the mitochondrial inner membrane. A possible substrate of Atm1p is an Fe/S cluster that may be stabilised for transport. Constituents of the cytosol involved in the incorporation of the Fe/S cluster into apoproteins have not been described yet. Many of the mitochondrial proteins involved in Fe/S cluster formation are essential, illustrating the central importance of Fe/S proteins for life. Defects in Fe/S protein biogenesis are associated with the abnormal accumulation of iron within mitochondria and are the cause of an iron storage disease.
Lill
R
R
Institut für Zytobiologie und Zytopathologie der Philipps-Universität Marburg, Germany.
Diekert
K
K
Kaut
A
A
Lange
H
H
Pelzer
W
W
Prohl
C
C
Kispal
G
G
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000096:biosynthesis*; D008928:Mitochondria / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D007506:Iron-Sulfur Proteins