Campos OA, Attar N, Cheng C, Vogelauer M, Mallipeddi NV, Schmollinger S, Matulionis N, Christofk HR, Merchant SS, Kurdistani SK. A pathogenic role for histone H3 copper reductase activity in a yeast model of Friedreich's ataxia. Sci Adv. 2021 Dec 17;7(51):eabj9889. doi: 10.1126/sciadv.abj9889. Epub 2021 Dec 17.
Disruptions to iron-sulfur (Fe-S) clusters, essential cofactors for a broad range of proteins, cause widespread cellular defects resulting in human disease. An underappreciated source of damage to Fe-S clusters are cuprous (Cu1+) ions. Since histone H3 enzymatically produces Cu1+ to support copper-dependent functions, we asked whether this activity could become detrimental to Fe-S clusters. Here, we report that histone H3-mediated Cu1+ toxicity is a major determinant of cellular Fe-S cluster quotient. Inadequate Fe-S cluster supply, either due to diminished assembly as occurs in Friedreich's Ataxia or defective distribution, causes severe metabolic and growth defects in S. cerevisiae. Decreasing Cu1+ abundance, through attenuation of histone cupric reductase activity or depletion of total cellular copper, restored Fe-S cluster-dependent metabolism and growth. Our findings reveal a novel interplay between chromatin and mitochondria in Fe-S cluster homeostasis, and a potential pathogenic role for histone enzyme activity and Cu1+ in diseases with Fe-S cluster dysfunction.
