FLX1 encodes a member of the mitochondrial carrier family that specifically transports flavin adenine dinucleotide (FAD) across the mitochondrial membrane (3, 1); it is still under debate as to whether Flx1p imports FAD into the mitochondria or exports it to the cytoplasm (2, 1). S. cerevisiae flx1 null mutants have respiratory defects and are unable to grow on nonfermentable carbon sources such as glycerol (1). Additionally, in flx1 mutant strains, the activities of FAD-containing lipoamide dehydrogenase (Lpd1p) and succinate dehydrogenase (a complex comprised of Sdh1p, Sdh2p, Sdh3p, and Sdh4p) are greatly reduced (2, 1). A human ortholog has been identified, mutations in which may cause some forms of the genetic disease multiple acyl-CoA dehydrogenase deficiency/glutaric aciduria type II (OMIM), which is characterized by defects in fatty acid, amino acid, and choline metabolism (4).

Last updated: 2006-08-23