title: The mitochondrial outer membrane protein Mas22p is essential for protein import and viability of yeast.
abstract: We have cloned the gene encoding the protein Mas22p, which spans the outer membrane of yeast mitochondria. Cells that completely lack Mas22p are inviable. The plasmid-borne MAS22 gene suppresses several defects resulting from the deletion of one or more of the mitochondrial protein import receptors. Defects of Mas20p-deficient cells are explained by the reduced level of Mas22p in these mutants. Mas22p has one acidic domain in the cytosol and a second acidic domain in the mitochondrial intermembrane space. We suggest that these domains of Mas22p on either side of the outer membrane function as a relay system for transferring the basic targeting sequences of precursor proteins into the mitochondria.
authors.affiliation: Biozentrum, Universität Basel, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Lithgow
authors.forename: T
authors.initials: T
authors.lastname: Junne
authors.forename: K
authors.initials: K
authors.lastname: Suda
authors.forename: S
authors.initials: S
authors.lastname: Gratzer
authors.forename: G
authors.initials: G
authors.lastname: Schatz
mesh_terms: D000595:Amino Acid Sequence; D015825:Chromosomes, Fungal; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D005800:Genes, Fungal; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D008961:Models, Structural; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; C090857:TOM22 protein, S cerevisiae