Sulfur Administration in Fe-S Cluster Homeostasis.

Mitochondria are the key organelles of Fe-S cluster synthesis. They contain the enzyme cysteine desulfurase, a scaffold protein, iron and electron donors, and specific chaperons all required for the formation of Fe-S clusters. The newly formed cluster can be utilized by mitochondrial Fe-S protein synthesis or undergo further transformation. Mitochondrial Fe-S cluster biogenesis components are required in the cytosolic iron-sulfur cluster assembly machinery for cytosolic and nuclear cluster supplies. Clusters that are the key components of Fe-S proteins are vulnerable and prone to degradation whenever exposed to oxidative stress. However, once degraded, the Fe-S cluster can be resynthesized or repaired. It has been proposed that sulfurtransferases, rhodanese, and 3-mercaptopyruvate sulfurtransferase, responsible for sulfur transfer from donor to nucleophilic acceptor, are involved in the Fe-S cluster formation, maturation, or reconstitution. In the present paper, we attempt to sum up our knowledge on the involvement of sulfurtransferases not only in sulfur administration but also in the Fe-S cluster formation in mammals and yeasts, and on reconstitution-damaged cluster or restoration of enzyme's attenuated activity.