Frataxin and mitochondrial iron-sulfur cluster assembly machinery (FXN-ISC complex)

Frataxin is a nuclear-encoded mitochondrial protein that acts as an essential allosteric activator of the mitochondrial iron-sulfur (Fe-S) cluster (ISC) assembly machinery (UniProt Q16595). This machinery is a multi-protein complex comprising the cysteine desulfurase NFS1, the scaffold protein ISCU, and the accessory proteins ISD11 and ACP, which together synthesize Fe-S clusters required for mitochondrial respiration and other metabolic pathways (PMID: 32649861). A deficiency in frataxin leads to Friedreich's ataxia (FA), a progressive neurodegenerative and cardiac disease characterized by impaired Fe-S cluster biogenesis, mitochondrial iron accumulation, and increased oxidative stress (PMID: 30635119). Therapeutic interventions targeting this complex include frataxin replacement therapies, gene therapies like LX2006, and small molecules such as Omaveloxolone that mitigate downstream mitochondrial dysfunction (FDA, 2023; ClinicalTrials.gov NCT05445323). Current research also explores small molecules that can stabilize the interaction between frataxin and the ISC machinery to enhance residual protein function (PMID: 28803779).

Other names

FXNCysteine desulfurase complexISC machineryFriedreich ataxia proteinNFS1-ISCU-ISD11-FXN complexMitochondrial iron-sulfur cluster assembly complex

Restoration of frataxin protein levels via gene or protein replacement, stabilization of the NFS1-ISCU-FXN complex to promote iron-sulfur cluster biogenesis, and activation of Nrf2-mediated antioxidant responses to mitigate mitochondrial dysfunction.