Performs an essential function in the generation of cytoplasmic iron-sulfur proteins by mediating export of Fe/S cluster precursors synthesized by NFS1 and other mitochondrial proteins. Not required for mitochondrial and plastid Fe-S enzymes. Probably involved in the export of cyclic pyranopterin monophosphate (cPMP) from mitochondria into the cytosol. Mediates glutathione-dependent resistance to heavy metals such as cadmium and lead, as well as their transport from roots to leaves. Regulates nonprotein thiols (NPSH) and the cellular level of glutathione (GSH). Cofactor biosynthesis; molybdopterin biosynthesis. Homodimer. Expressed at high levels in roots, leaves, stems, flowers and siliques. In roots by cadmium and lead. Plants exhibit an enhanced sensitivity to cadmium, dwarfism and chlorosis, with an altered morphology of leaf and cell nuclei. Mitochondria accumulate nonheme, nonprotein iron. Decreased levels of molybdenum cofactor (MOCO) and reduced activities of cytosolic Fe-S proteins. Reduced ability to produce abscisic acid under normal conditions and in response to drought stress. Male sterility when homozygous. Belongs to the ABC transporter superfamily. ABCB family. Heavy Metal importer (TC 3.A.1.210) subfamily.