A Conserved Mitochondrial ATP-binding Cassette Transporter Exports Glutathione Polysulfide for Cytosolic Metal Cofactor Assembly

• DOI: 10.1074/jbc.m114.553438
• Publication Date: 2014-07-09T05:36:03Z
• Authors: Theresia A. Schae...; Jeremy D. Thornton; Inga Kruse; Markus Schwarzländer; Andreas J. Meyer; Hendrik W. van Veen; Janneke Balk
• Keywords: 570; Saccharomyces cerevisiae Proteins; Transportomics; Molecular Sequence Data; Arabidopsis; Saccharomyces cerevisiae; Sulfides; Mitochondrial Proteins; 03 medical and health sciences; Cytosol; Iron-Sulfur Protein; Amino Acid Sequence; Conserved Sequence; Adenosine Triphosphatases; 0303 health sciences; Sequence Homology, Amino Acid; Arabidopsis Proteins; Biological Transport; Cell Biology; Glutathione; Yeast; Mitochondria; ABC Transporter; Metals; ATP-Binding Cassette Transporters

An ATP-binding cassette transporter located in the inner mitochondrial membrane is involved in iron-sulfur cluster and molybdenum cofactor assembly in the cytosol, but the transported substrate is unknown. ATM3 (ABCB25) from Arabidopsis thaliana and its functional orthologue Atm1 from Saccharomyces cerevisiae were expressed in Lactococcus lactis and studied in inside-out membrane vesicles and in purified form. Both proteins selectively transported glutathione disulfide (GSSG) but not reduced glutathione in agreement with a 3-fold stimulation of ATPase activity by GSSG. By contrast, Fe(2+) alone or in combination with glutathione did not stimulate ATPase activity. Arabidopsis atm3 mutants were hypersensitive to an inhibitor of glutathione biosynthesis and accumulated GSSG in the mitochondria. The growth phenotype of atm3-1 was strongly enhanced by depletion of the mitochondrion-localized, GSH-dependent persulfide oxygenase ETHE1, suggesting that the physiological substrate of ATM3 contains persulfide in addition to glutathione. Consistent with this idea, a transportomics approach using mass spectrometry showed that glutathione trisulfide (GS-S-SG) was transported by Atm1. We propose that mitochondria export glutathione polysulfide, containing glutathione and persulfide, for iron-sulfur cluster assembly in the cytosol.