title: Yeast translational activator Cbs2p: mitochondrial targeting and effect of overexpression.
abstract: The yeast translational activator protein Cbs2p is imported into mitochondria without obvious proteolytic processing. To test the importance of amino-terminal amino acids for mitochondrial targeting we fused varying portions of the N-terminus with green fluorescent protein and examined the intracellular distribution of the reporter protein. We show that the 25 N-terminal amino acids are sufficient to direct the majority of the fusion protein into mitochondria. Cbs2p derivatives lacking 9 to 35 amino acids from the N-terminus fail to complement the respiratory deficiency of a deltacbs2 strain, but are still imported into mitochondria. Therefore Cbs2p contains at least one independent mitochondrial targeting information in addition to the N-terminal signal. We further analyzed the effect of over-expression of Cbs2p on mitochondrial function. Elevated concentrations of Cbs2p lead to slightly impaired mitochondrial gene expression, probably as the result of the formation of inactive Cbs2p aggregates.
authors.affiliation: Institut für Genetik, Technische Universität Dresden, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Tzschoppe
authors.forename: S D
authors.initials: SD
authors.lastname: Kohlwein
authors.forename: G
authors.initials: G
authors.lastname: Rödel
mesh_terms: D020816:Amino Acid Motifs; D001692:Biological Transport; D005656:Fungal Proteins / Q000378:metabolism / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects; D021382:Protein Sorting Signals / Q000235:genetics*; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014170:Transformation, Genetic
chemical_list: C401826:CBS2 protein, S cerevisiae; D005656:Fungal Proteins; D008164:Luminescent Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D049452:Green Fluorescent Proteins; D011451:Prostaglandin-Endoperoxide Synthases