title: Genetic and biochemical characterization of ISP6, a small mitochondrial outer membrane protein associated with the protein translocation complex.
abstract: To search genetically for additional components of the protein translocation apparatus of mitochondria, we have used low fidelity PCR mutagenesis to generate temperature-sensitive mutants in the outer membrane translocation pore component ISP42. A high copy number suppressor of temperature-sensitive isp42 has been isolated and sequenced. This novel gene, denoted ISP6, encodes a 61 amino acid integral membrane protein of the mitochondrial outer membrane, which is oriented with its amino-terminus facing the cytosol. Disruption of the ISP6 gene is without apparent effect in wild type yeast cells, but is lethal in temperature-sensitive isp42 mutants. Immunoprecipitation of the gene product, ISP42p, from mitochondria solubilized under mild conditions reveals a multi-protein complex containing ISP6p and ISP42p.
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina, School of Medicine, Chapel Hill 27599-7260.
authors.forename: C K
authors.initials: CK
authors.lastname: Kassenbrock
authors.forename: W
authors.initials: W
authors.lastname: Cao
authors.forename: M G
authors.initials: MG
authors.lastname: Douglas
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D016153:Genes, Suppressor; D006358:Hot Temperature; D007425:Intracellular Membranes / Q000378:metabolism*; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; C082532:TOM6 protein, S cerevisiae; C066555:Tom40 protein, S cerevisiae