Monothiol glutaredoxin involved in mitochondrial iron-sulfur (Fe/S) cluster transfer (, ). Receives 2Fe/2S clusters from scaffold protein ISCU and mediates their transfer to apoproteins, to the 4Fe/FS cluster biosynthesis machinery, or export from mitochondrion ( ). Required for normal regulation of hemoglobin synthesis by the iron-sulfur protein ACO1 .
Subcellular locations: Mitochondrion matrix