bims-resufa Biomed News
on Respiratory supercomplex factors
Issue of 2025–08–03
two papers selected by
Gavin McStay, Liverpool John Moores University
  1. Nitrosative stress affects mitochondrial respiratory chain complex II and complex IV assemblies in Saccharomyces cerevisiae: S-nitrosylation of complex II.
  2. Cardiolipin acyl chain composition tailors the conformation of mammalian ATP synthase dimers.
  1. Biochim Biophys Acta Gen Subj. 2025 Jul 30. pii: S0304-4165(25)00090-X. [Epub ahead of print] 130845
    Nitrosative stress affects mitochondrial respiratory chain complex II and complex IV assemblies in Saccharomyces cerevisiae: S-nitrosylation of complex II.
    Sanchita Biswas, Ayantika Sengupta, Shubhojit Das, Chirandeep Dey, Rajib Sengupta, Alok Ghosh, Sanjay Ghosh.
      The elevated level of nitric oxide (NO) and reactive nitrogen species (RNS) induce nitrosative stress in cells and inhibit mitochondrial respiration. Reports showed that RNS rapidly inactivate complex I, followed by inhibition of complex II, III and IV in isolated mitochondria. However, the mechanism(s) by which NO and RNS inhibit these complexes still unclear. In this study facultative anaerobic yeast Saccharomyces cerevisiae has been used for investigating mitochondrial respiratory dysfunction under nitrosative stress, as four out of five mitochondrial oxidative pHosphorylation complexes i.e. complexes II, III, IV and V are structurally conserved from yeast to human. Using microbiological growth assays, we showed that S. cerevisiae wild type W3O3 cells treated with graded concentration of sodium nitroprusside (SNP) and S-Nitrosoglutathione (GSNO) induce nitrosative stress, and cell growth was severely compromised under the respiratory proficient rich glycerol-ethanol media. Both the whole cell and the mitochondrial oxygen consumption rates were also significantly compromised under nitrosative stress. Surprisingly, mitochondrial respiratory chain complex II succinate dehydrogenase (SDH) of S. cerevisiae was found S-nitrosylated and therefore inactivated under nitrosative stress. Endogenous RNS produced by S-nitrosoglutathione reductase mutant cells of S. cerevisiae also showed increased S-nitrosylation of SDH. Complex III and IV activities were irreversibly inhibited in S. cerevisiae under nitrosative stress. Interestingly, protein tyrosine nitration was also enhanced in mitochondria in a dose dependent manner upon SNP treatment. Reduced expressions of both Sdh2 (succinate dehydrogenase subunit-2) and Cox2 (mitochondrial complex IV subunit) were observed at the transcription and translation level in S. cerevisiae under nitrosative stress. Blue Native-PAGE followed by Western blotting analysis, further revealed significantly reduced native complex II and the complex III and IV containing super-complexes assemblies in consequences of nitrosative stress in S. cerevisiae. Henceforth, the present in vivo study provides for the first-time novel information on the modification of mitochondrial complexes under nitrosative stress which in turn regulates the mitochondrial respiratory chain complexes assembly in S. cerevisiae.
    Keywords:  Mitochondrial respiratory chain complex; Nitrosative stress; S-nitrosylation; Saccharomyces cerevisiae; Succinate dehydrogenase
    DOI:  https://doi.org/10.1016/j.bbagen.2025.130845
  2. Commun Chem. 2025 Jul 30. 8(1): 220
    Cardiolipin acyl chain composition tailors the conformation of mammalian ATP synthase dimers.
    M Makowski, V G Almendro-Vedia, I López-Montero.
      The interplay between ATP synthase dimers and the four-tailed lipid cardiolipin (CL) shapes mitochondrial cristae structure and function. In the mitochondrial disorder Barth syndrome (BTHS), cristae membranes accumulate a less unsaturated, three-tailed form of cardiolipin (MLCL). These cristae become structurally and functionally compromised through mechanisms poorly understood. We have studied through molecular dynamics simulations how BTHS lipid composition affects the conformation of the ATP synthase dimer. The wedge-shaped transmembrane region of the ATP synthase dimer attracts cardiolipins through shape complementarity. MLCL showed decreased affinity for the dimer interface than CLs of the healthy model. A more heterogeneous lipid environment with a higher elastic strain promoted a dimer conformation that would stabilize wider intracrista spaces, and hence, less efficient OXPHOS reactions in BTHS. Our results provide clues on the role played by the CL acyl chain composition in the architecture and function of mitochondria in health and BTHS.
    DOI:  https://doi.org/10.1038/s42004-025-01611-1
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