[ODP4F] f. Microbial Metabolism

[ODP-078/WS6-5] Longevity is dependent on sulfide:quinone oxidoreductase mediated energy metabolism in fission yeast

○Masanobu Morita¹, Akira Nishimura², Tomoaki Ida¹, Minkyung Jung¹, Tetsuro Matsunaga¹, Tsuyoshi Takata¹, Hozumi Motohashi³, Takaaki Akaike¹ (¹Dept. Environ. Med. Mol. Toxicol., Tohoku Univ. Grad. Sch. Med., ²Grad. Sch. Biol. Sci., NAIST, ³Dept. Gene Expression Regulation, IDAC, Tohoku Univ.)

Sulfide:quinone oxidoreductase (SQR) is highly conserved enzyme in nearly all organisms and has been proposed to mediate sulfur metabolism in mitochondria. Our recent finding showed that SQR is involved in oxygen-independent novel energy metabolism, sulfur respiration. Eukaryotic SQR was first identified in fission yeast of Schizosaccharomyces pombe as a cadmium (Cd) detoxifying enzyme. To confirm this activity, we established SQR-deficient yeast and tested Cd-cytotoxicity assay where SQR-deficient yeast showed enhanced susceptibility to Cd toxicity. We then examined the involvement of SQR in the mitochondrial energy metabolism in different carbon sources. Both wild-type (WT) and SQR-deficient yeast showed normal growth in glucose medium, suggesting that SQR is dispensable for glycolytic energy production. When glycerol was the sole carbon source, SQR-deficient yeast showed defective growth, indicative of essential role of SQR for the mitochondrial energy metabolism. Mitochondrial membrane potential, ATP production and lifespan were significantly reduced in SQR-deficient yeast compared with WT yeast. Moreover, administration of hydrogen sulfide or persulfide donors extended lifespan of WT yeast but not of SQR-deficient yeast. Taken together, these data allow us to understand the physiological mechanism of sulfur respiration conserved between prokaryotes and eukaryotes.