title: Identification of mitochondrial carriers in Saccharomyces cerevisiae by transport assay of reconstituted recombinant proteins.
abstract: The inner membranes of mitochondria contain a family of carrier proteins that are responsible for the transport in and out of the mitochondrial matrix of substrates, products, co-factors and biosynthetic precursors that are essential for the function and activities of the organelle. This family of proteins is characterized by containing three tandem homologous sequence repeats of approximately 100 amino acids, each folded into two transmembrane alpha-helices linked by an extensive polar loop. Each repeat contains a characteristic conserved sequence. These features have been used to determine the extent of the family in genome sequences. The genome of Saccharomyces cerevisiae contains 34 members of the family. The identity of five of them was known before the determination of the genome sequence, but the functions of the remaining family members were not. This review describes how the functions of 15 of these previously unknown transport proteins have been determined by a strategy that consists of expressing the genes in Escherichia coli or Saccharomyces cerevisiae, reconstituting the gene products into liposomes and establishing their functions by transport assay. Genetic and biochemical evidence as well as phylogenetic considerations have guided the choice of substrates that were tested in the transport assays. The physiological roles of these carriers have been verified by genetic experiments. Various pieces of evidence point to the functions of six additional members of the family, but these proposals await confirmation by transport assay. The sequences of many of the newly identified yeast carriers have been used to characterize orthologs in other species, and in man five diseases are presently known to be caused by defects in specific mitochondrial carrier genes. The roles of eight yeast mitochondrial carriers remain to be established.
authors.affiliation: Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via E. Orabona 4, 70125 Bari, Italy. fpalm@farmbiol.uniba.it
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Palmieri
authors.forename: Gennaro
authors.initials: G
authors.lastname: Agrimi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Blanco
authors.forename: Alessandra
authors.initials: A
authors.lastname: Castegna
authors.forename: Maria A
authors.initials: MA
authors.lastname: Di Noia
authors.forename: Vito
authors.initials: V
authors.lastname: Iacobazzi
authors.forename: Francesco M
authors.initials: FM
authors.lastname: Lasorsa
authors.forename: Carlo M T
authors.initials: CM
authors.lastname: Marobbio
authors.forename: Luigi
authors.initials: L
authors.lastname: Palmieri
authors.forename: Pasquale
authors.initials: P
authors.lastname: Scarcia
authors.forename: Simona
authors.initials: S
authors.lastname: Todisco
authors.forename: Angelo
authors.initials: A
authors.lastname: Vozza
authors.forename: John
authors.initials: J
authors.lastname: Walker
mesh_terms: D001692:Biological Transport; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D000226:Mitochondrial ADP, ATP Translocases