FXN Protein, Rat

FXN Protein acts as an activator in the persulfide transfer process within the core iron-sulfur cluster (ISC) assembly complex, essential for [2Fe-2S] cluster assembly. It facilitates sulfur transfer from NFS1 persulfide intermediate to ISCU and small thiols like L-cysteine and glutathione, leading to persulfuration and sulfide release. During [2Fe-2S] cluster assembly, FXN binds ferrous ion and is released upon the addition of L-cysteine and reduced FDX2. The ISC assembly complex, comprising FXN, NFS1, LYRM4, NDUFAB1, and FDX2, initiates de novo synthesis of [2Fe-2S] clusters, transferring them to chaperone proteins like HSCB, HSPA9, and GLRX5. FXN may protect against iron-catalyzed oxidative stress, displaying ferroxidase activity in its oligomeric form. It might function as an iron chaperone, safeguarding aconitase [4Fe-4S]2+ clusters, participating in mitochondrial heme biosynthesis, and modulating the RNA-binding activity of ACO1. Additionally, FXN could contribute to cytoplasmic iron-sulfur protein biogenesis, oxidative stress resistance, and overall cell survival.