Control of oxygen free radical formation from mitochondrial complex I: roles for protein kinase A and pyruvate dehydrogenase kinase

Free Radic Biol Med. 2002 Mar 1;32(5):421-30. doi: 10.1016/s0891-5849(01)00816-4.

Abstract

Human NADH CoQ oxidoreductase is composed of a total of 43 subunits and has been demonstrated to be a major site for the production of superoxide by mitochondria. Incubation of rat heart mitochondria with ATP resulted in the phosphorylation of two mitochondrial membrane proteins, one with a M(r) of 6 kDa consistent with the NDUFA1 (MWFE), and one at 18kDa consistent with either NDUFS4 (AQDQ) or NDUFB7 (B18). Phosphorylation of both subunits was enhanced by cAMP derivatives and protein kinase A (PKA) and was inhibited by PKA inhibitors (PKAi). When mitochondrial membranes were incubated with pyruvate dehydrogenase kinase, phosphorylation of an 18kDa protein but not a 6kDa protein was observed. NADH cytochrome c reductase activity was decreased and superoxide production rates with NADH as substrate were increased. On the other hand, with protein kinase A-driven phosphorylation, NADH cytochrome c reductase was increased and superoxide production decreased. Overall there was a 4-fold variation in electron transport rates observable at the extremes of these phosphorylation events. This suggests that electron flow through complex I and the production of oxygen free radicals can be regulated by phosphorylation events. In light of these observations we discuss a potential model for the dual regulation of complex I and the production of oxygen free radicals by both PKA and PDH kinase.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Blotting, Western
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / pharmacology*
  • Electron Transport Complex I
  • Enzyme Activation
  • Firefly Luciferin / metabolism
  • Humans
  • Imidazoles*
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / metabolism
  • Mitochondria, Heart / drug effects*
  • Mitochondria, Heart / enzymology
  • NAD / metabolism
  • NADH Dehydrogenase / metabolism
  • NADH, NADPH Oxidoreductases / antagonists & inhibitors
  • NADH, NADPH Oxidoreductases / metabolism*
  • Oxygen Consumption
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors
  • Protein Kinases / pharmacology*
  • Protein-Serine-Threonine Kinases
  • Pyrazines / metabolism
  • Pyruvate Dehydrogenase (Acetyl-Transferring) Kinase
  • Rats
  • Rats, Wistar
  • Reactive Oxygen Species / metabolism*
  • Superoxides / metabolism

Substances

  • Imidazoles
  • Membrane Proteins
  • Ndufa1 protein, mammalian
  • Protein Kinase Inhibitors
  • Pyrazines
  • Pyruvate Dehydrogenase (Acetyl-Transferring) Kinase
  • Reactive Oxygen Species
  • NAD
  • Superoxides
  • coelenterazine
  • Firefly Luciferin
  • Adenosine Triphosphate
  • Cyclic AMP
  • NADH, NADPH Oxidoreductases
  • NADH Dehydrogenase
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • Cyclic AMP-Dependent Protein Kinases
  • Electron Transport Complex I
  • NDUFA1 protein, human
  • NDUFS4 protein, human