title: Dynamic regulation of mitochondrial respiratory chain efficiency in Saccharomyces cerevisiae.
abstract: To adapt to changes in the environment, cells have to dynamically alter their phenotype in response to, for instance, temperature and oxygen availability. Interestingly, mitochondrial function in Saccharomyces cerevisiae is inherently temperature sensitive; above 37 °C, yeast cells cannot grow on respiratory carbon sources. To investigate this phenomenon, we studied the effect of cultivation temperature on the efficiency (production of ATP per atom of oxygen consumed, or P/O) of the yeast respiratory chain in glucose-limited chemostats. We determined that even though the specific oxygen consumption rate did not change with temperature, oxygen consumption no longer contributed to mitochondrial ATP generation at temperatures higher than 37 °C. Remarkably, between 30 and 37 °C, we observed a linear increase in respiratory efficiency with growth temperature, up to a P/O of 1.4, close to the theoretical maximum that can be reached in vivo. The temperature-dependent increase in efficiency required the presence of the mitochondrial glycerol-3-phosphate dehydrogenase GUT2. Respiratory chain efficiency was also altered in response to changes in oxygen availibility. Our data show that, even in the absence of alternative oxidases or uncoupling proteins, yeast has retained the ability to dynamically regulate the efficiency of coupling of oxygen consumption to proton translocation in the respiratory chain in response to changes in the environment.
authors.affiliation: Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Jarne
authors.initials: J
authors.lastname: Postmus
authors.affiliation: Department of Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Işil
authors.initials: I
authors.lastname: Tuzun
authors.affiliation: Department of Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Bekker
authors.affiliation: Department of Biology, Biomolecular Imaging, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Wally H
authors.initials: WH
authors.lastname: Müller
authors.affiliation: Department of Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: M Joost
authors.initials: MJ
authors.lastname: Teixeira de Mattos
authors.affiliation: Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Stanley
authors.initials: S
authors.lastname: Brul
authors.affiliation: Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Gertien J
authors.initials: GJ
authors.lastname: Smits
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D004579:Electron Transport; D015966:Gene Expression Regulation, Fungal; D008928:Mitochondria / Q000201:enzymology* / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000502:physiology*; D013696:Temperature
chemical_list: D000255:Adenosine Triphosphate; D010088:Oxidoreductases; D010100:Oxygen