FIGURE 1  Frataxin function and oxidative stress in Friedreich ataxia.

Figure 1.  Frataxin function and oxidative stress in Friedreich ataxia.

Several of the postulated functions of frataxin are represented, including the provision of iron for iron–sulfur clusters and heme synthesis, and direct interaction with respiratory chain complexes. Green arrows and text indicate molecules and pathways that have decreased activity in frataxin deficiency; red arrows and text indicate molecules and pathways that have increased activity in frataxin deficiency. Abbreviations: Aco, aconitase; CI, respiratory chain complex I; CII, respiratory chain complex II; CIII, respiratory chain complex III; CIV, respiratory chain complex IV; CV, respiratory chain complex V; Cys, cysteine; cyt c, cytochrome c; e^-, electron; FECH, ferrochelatase; FRDA, frataxin; GPx, glutathione peroxidase; GSH, reduced glutathione; GSSG, oxidized glutathione; H₂O₂, hydrogen peroxide; IscS, cysteine desulfurase; IscU, iron–sulfur cluster scaffold protein; IX, protoporphyrin IX; OH, hydroxyl radical; Q, coenzyme Q; SOD, superoxide dismutase.

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