title: Mitochondrial Efficiency-Dependent Viability of Saccharomyces cerevisiae Mutants Carrying Individual Electron Transport Chain Component Deletions.
abstract: Mitochondria play a crucial role in eukaryotic cells; the mitochondrial electron transport chain (ETC) generates adenosine triphosphate (ATP), which serves as an energy source for numerous critical cellular activities. However, the ETC also generates deleterious reactive oxygen species (ROS) as a natural byproduct of oxidative phosphorylation. ROS are considered the major cause of aging because they damage proteins, lipids, and DNA by oxidation. We analyzed the chronological life span, growth phenotype, mitochondrial membrane potential (MMP), and intracellular ATP and mitochondrial superoxide levels of 33 single ETC component-deleted strains during the chronological aging process. Among the ETC mutant strains, 14 (sdh1Δ, sdh2Δ, sdh4Δ, cor1Δ, cyt1Δ, qcr7Δ, qcr8Δ, rip1Δ, cox6Δ, cox7Δ, cox9Δ, atp4Δ, atp7Δ, and atp17Δ) showed a significantly shorter life span. The deleted genes encode important elements of the ETC components succinate dehydrogenase (complex II) and cytochrome c oxidase (complex IV), and some of the deletions lead to structural instability of the membrane-F1F0-ATP synthase due to mutations in the stator stalk (complex V). These short-lived strains generated higher superoxide levels and produced lower ATP levels without alteration of MMP. In summary, ETC mutations decreased the life span of yeast due to impaired mitochondrial efficiency.
authors.affiliation: Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Young-Yon
authors.initials: YY
authors.lastname: Kwon
authors.affiliation: Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Kyung-Mi
authors.initials: KM
authors.lastname: Choi
authors.affiliation: Animal Genetic Resources Research Center, National Institute of Animal Science, Rural Development Administration, Jeonbuk 590-832, Korea.
authors.forename: ChangYeon
authors.initials: C
authors.lastname: Cho
authors.affiliation: Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Cheol-Koo
authors.initials: CK
authors.lastname: Lee
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D045222:Electron Transport Chain Complex Proteins / Q000235:genetics*; D017353:Gene Deletion; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D013481:Superoxides / Q000378:metabolism
chemical_list: D045222:Electron Transport Chain Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; D013481:Superoxides; D000255:Adenosine Triphosphate
keywords: ETC-component single gene deletion; cellular ATP; electron transport chain; mitochondria; mitochondrial ROS