1. Fine-tuning of the respiratory complexes stability and supercomplexes assembly in cells defective of complex III
- Author
-
Letizia Scandiffio, Claudia Zanna, Michela Rugolo, Jessica Fiori, Stefan Steimle, Fevzi Daldal, Serena J. Aleo, Marina Roberti, Aldo Roda, Paola Loguercio Polosa, Anna Ghelli, Valerio Carelli, Emanuele Porru, Concetta Valentina Tropeano, Tropeano C.V., Aleo S.J., Zanna C., Roberti M., Scandiffio L., Loguercio Polosa P., Fiori J., Porru E., Roda A., Carelli V., Steimle S., Daldal F., Rugolo M., and Ghelli A.
- Subjects
0301 basic medicine ,N-acetylcysteine, rotenone ,Biophysics ,MT-CYB gene in-frame microdeletion ,Mitochondrion ,medicine.disease_cause ,Biochemistry ,Article ,Electron Transport Complex IV ,03 medical and health sciences ,chemistry.chemical_compound ,Electron Transport Complex III ,0302 clinical medicine ,Adenosine Triphosphate ,Oxygen Consumption ,Rotenone ,medicine ,Animals ,Mutation ,Electron Transport Complex I ,ATP synthase ,biology ,Animal ,Cell Biology ,Mitochondria ,Respiratory chain supercomplexe ,030104 developmental biology ,chemistry ,Cytochrome b depletion complex III dysfunction ,Coenzyme Q – cytochrome c reductase ,Respirasome ,Mitochondrial Membranes ,biology.protein ,Mitochondrial Membrane ,lipids (amino acids, peptides, and proteins) ,Adenosine triphosphate ,Oxidation-Reduction ,030217 neurology & neurosurgery ,Gene Deletion - Abstract
The respiratory complexes are organized in supramolecular assemblies called supercomplexes thought to optimize cellular metabolism under physiological and pathological conditions. In this study, we used genetically and biochemically well characterized cells bearing the pathogenic microdeletion m.15,649–15,666 (ΔI300-P305) in MT-CYB gene, to investigate the effects of an assembly-hampered CIII on the re-organization of supercomplexes. First, we found that this mutation also affects the stability of both CI and CIV, and evidences the occurrence of a preferential structural interaction between CI and CIII(2), yielding a small amount of active CI+CIII(2) super-complex. Indeed, a residual CI+CIII combined redox activity, and a low but detectable ATP synthesis driven by CI substrates are detectable, suggesting that the assembly of CIII into the CI+CIII(2) supercomplex mitigates the detrimental effects of MT-CYB deletion. Second, measurements of oxygen consumption and ATP synthesis driven by NADH-linked and FADH(2)-linked substrates alone, or in combination, indicate a common ubiquinone pool for the two respiratory pathways. Finally, we report that prolonged incubation with rotenone enhances the amount of CI and CIII(2), but reduces CIV assembly. Conversely, the antioxidant N-acetylcysteine increases CIII(2) and CIV(2) and partially restores respirasome formation. Accordingly, after NAC treatment, the rate of ATP synthesis increases by two-fold compared with untreated cell, while the succinate level, which is enhanced by the homoplasmic mutation, markedly decreases. Overall, our findings show that fine-tuning the supercomplexes stability improves the energetic efficiency of cells with the MT-CYB microdeletion.
- Published
- 2019