Fig. 4

Short-lived strains, lon1Δ and yta12Δ, display dysfunctional mitochondria. A lon1Δ and yta12Δ exhibit a growth defect under low glucose conditions. 972 (WT), lon1Δ, yta12Δ, mgr3Δ, yme1Δ, and cox6Δ strains were grown in rich media (YE) with 3% glucose and minimal media (MM) with 2% glucose. Serial dilutions of logarithmically growing cells were spotted onto YE containing 3% or 0.08% glucose and MM containing 2% or 0.08% glucose plates. B Differences in oxygen consumption levels of mitoprotease mutants and mgr3Δ. The indicated strains were grown in rich media with 3% or 0.08% glucose. Oxygen consumption was measured when cultures reached an OD₆₀₀ of 0.5. Data from three biological replicates are shown. Significant differences between deletion strains and wild type were determined by two-sided t-test (*p < 0.05, **p < 0.01, ***p < 0.001). C Mitochondrial membrane potential (ΔΨ) is reduced in cells lacking the protease Yta12. Mitochondria of the indicated strains were stained with MitoTracker red and ΔΨ was determined by fluorescence microscopy. Maximum and minimum levels were adjusted using Fiji (ImageJ, National Institutes of Health) [65]. The corresponding quantification is shown in Fig. S1. Scale bar, 5 μm. D Scheme depicting the localization of OXPHOS proteins encoded by mitochondrial DNA (mtDNA). E Short-lived strains have diminished steady-state levels of several mtDNA-encoded proteins. Mitochondrial TCA extracts of 972 (WT), lon1Δ, yta12Δ, mgr3Δ, and yme1Δ were analyzed by immunoblotting using antibodies against the mtDNA-encoded proteins Cox1, Cox2, Cox3, and Atp6. Sdh2-GFP was used as a loading control