Defective function of α-ketoglutarate dehydrogenase exacerbates mitochondrial ATP deficits during complex I deficiency

Redox Biol. 2023 Nov:67:102932. doi: 10.1016/j.redox.2023.102932. Epub 2023 Oct 17.


The NDUFS4 knockout (KO) mouse phenotype resembles the human Complex I deficiency Leigh Syndrome. The irreversible succination of protein thiols by fumarate is increased in select regions of the NDUFS4 KO brain affected by neurodegeneration. We report that dihydrolipoyllysine-residue succinyltransferase (DLST), a component of the α-ketoglutarate dehydrogenase complex (KGDHC) of the tricarboxylic acid (TCA) cycle, is succinated in the affected regions of the NDUFS4 KO brain. Succination of DLST reduced KGDHC activity in the brainstem (BS) and olfactory bulb (OB) of KO mice. The defective production of KGDHC derived succinyl-CoA resulted in decreased mitochondrial substrate level phosphorylation (SLP), further aggravating the existing oxidative phosphorylation (OXPHOS) ATP deficit. Protein succinylation, an acylation modification that requires succinyl-CoA, was reduced in the KO mice. Modeling succination of a cysteine in the spatial vicinity of the DLST active site or introduction of succinomimetic mutations recapitulates these metabolic deficits. Our data demonstrate that the biochemical deficit extends beyond impaired Complex I assembly and OXPHOS deficiency, functionally impairing select components of the TCA cycle to drive metabolic perturbations in affected neurons.

Keywords: Alpha-ketoglutarate dehydrogenase; Complex I; Fumarate; Leigh syndrome; Protein succination; Substrate level phosphorylation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Citric Acid Cycle*
  • Humans
  • Ketoglutarate Dehydrogenase Complex* / genetics
  • Ketoglutarate Dehydrogenase Complex* / metabolism
  • Mice
  • Mice, Knockout
  • Mitochondria / genetics
  • Mitochondria / metabolism
  • Oxidative Phosphorylation


  • Ketoglutarate Dehydrogenase Complex
  • Adenosine Triphosphate