Figure 2. npr2Δ mutant cells have defective mitochondrial function.

(a) Dissolved oxygen levels as a function of growth following inoculation into SD medium. WT and npr2Δ strains were grown in parallel bioreactor vessels, and dissolved oxygen amounts were monitored continuously. The OD₆₀₀ at corresponding time points were labeled for WT (grey) and npr2Δ (black). Representative data were selected from 3 independent experiments.

(b) Western blots indicating amounts of HA-tagged TCA cycle enzymes: Aco1p (aconitase), Cit1p (citrate synthase), Idh1p (isocitrate dehydrogenase), Kgd1p (α-ketoglutarate dehydrogenase), Lsc1p (succinyl-CoA ligase), Sdh1p (succinate dehydrogenase), Fum1p (fumarase) and Mdh1p (mitochondrial malate dehydrogenase) in WT and npr2Δ cells grown in SD for 6 hours. Total protein level (Coomassie blue stain) is shown as loading control. Full gels are shown in Supplementary Fig. 5b.

(c) Relative abundance of labeled TCA cycle metabolites from glucose-¹³C₆ tracing experiments. Labeled species are shown as percentage of all isotopomers of the respective metabolite. Glucose-¹³C₆ is converted into pyruvate. Pyruvate can be converted into acetyl-CoA, and all first round TCA cycle metabolites are M+2 labeled. The final product M+2 oxaloacetate in combination with M+2 labeled acetyl-CoA can give rise to second round metabolites. Pyruvate can also be converted into M+3 oxaloacetate and the TCA products are labeled as listed in Supplementary Table 2. Data were mean ± s.d. from 3 independent experiments. *p < 0.05, **p < 0.01, ***p<0.001, by two-tailed Student’s t-test.