Monothiol glutaredoxin involved in mitochondrial iron-sulfur (Fe/S) cluster transfer (PubMed:20085751, PubMed:23615440). Receives 2Fe/2S clusters from scaffold protein isu1 and mediates their transfer to apoproteins, to the 4Fe/FS cluster biosynthesis machinery, or export from mitochondrion (PubMed:20085751, PubMed:23615440). Homodimer (By similarity). Interacts with ISA1 and ISA2 (PubMed:20085751). By nitrosative and osmotic stresses. Belongs to the glutaredoxin family. Monothiol subfamily.