Fig. 6: MMEL and mitochondrial proteases contribute to the degradation of mitochondrial proteins. | Nature Communications

Fig. 6: MMEL and mitochondrial proteases contribute to the degradation of mitochondrial proteins.

From: Hypoxia-reprogramed megamitochondrion contacts and engulfs lysosome to mediate mitochondrial self-digestion

Fig. 6: MMEL and mitochondrial proteases contribute to the degradation of mitochondrial proteins.The alt text for this image may have been generated using AI.

a HeLa cells were treated with hypoxia for 0 h (normoxia), 24 h or 48 h, and then collected and used for mitochondrial purification. The concentration of mitochondrial proteins was measured by the Bradford assay. b, c HeLa cells were treated with hypoxia for 0 h (normoxia), 24 h, and 48 h. The whole cell lysates were then analyzed by Western blotting with the indicated antibodies (b). The relative protein levels were further evaluated by densitometry analysis using ImageJ software (c). d, e WT or ATG5 knockout (KO) MEFs were treated with hypoxia for 0 h (normoxia), 24 h, and 48 h. Cell lysates were then analyzed by Western blotting with the indicated antibodies (d). The relative protein levels were further evaluated by densitometry analysis using ImageJ software (e). f–i Control or Rab9 knockdown (shRab9) HeLa cells were exposed to hypoxia for 0 h (normoxia), 12 h, or 24 h. Control or STX17 knockdown (shSTX17) HeLa cells were exposed to hypoxia for 0 h (normoxia), 12 h, or 24 h. Cell lysates were then analyzed by Western blotting with the indicated antibodies (f, h). The relative protein levels were further evaluated by densitometry analysis using ImageJ software (g, i). j–n Control, cathepsin D and cathepsin B double knockdown (shCTSB+shCTSD) HCT116 cells were exposed to hypoxia for 0 h (normoxia), 12 h, and 24 h. Control (empty vector), OMA1-Yme1L double knockout (DKO) plus LONP1 knockdown (shLONP1) HCT116 cells were exposed to hypoxia for 0 h (normoxia), 12 h, and 24 h. Cell lysates were then analyzed by Western blotting using the indicated antibodies (j, m). The relative protein levels were further evaluated by densitometry analysis using ImageJ software (k, n). The relative levels of CTSB mRNA were analyzed by quantitative RT-PCR (l). Bars of (a, c and l) represent mean ± SD, n = 3 independent experiments, statistical significance was assessed by a one-way ANOVA. Bars of (e, g, i, k and n) represent mean ± SD, n = 3 independent experiments, statistical significance was assessed by two-tailed t-test. P values are indicated in the figure. Source data are provided as a Source Data file.

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