Mitochondrial quinone redox states as a marker of mitochondrial metabolism

• Published in: Biochimica et biophysica acta. Bioenergetics Vol. 1865; no. 2; p. 149033
• Main Authors: Martins Pinto, M., Ransac, S., Mazat, J.P., Schwartz, L., Rigoulet, M., Arbault, S., Paumard, P., Devin, A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2024
• Subjects: Bioenergetics; Mitochondria respiratory chain; Quinones; Redox state; Q2; Redox state; G3P; EtOH; ADP; OAA; Quinones; CCCP; NADH; Bioenergetics; α-KG; CIII; Mitochondria respiratory chain; ATP
• ISSN: 0005-2728; 1879-2650; 1879-2650
• DOI: 10.1016/j.bbabio.2024.149033

Mitochondrial and thus cellular energetics are highly regulated both thermodynamically and kinetically. Cellular energetics is of prime importance in the regulation of cellular functions since it provides ATP for their accomplishment. However, cellular energetics is not only about ATP production but also about the ability to re-oxidize reduced coenzymes at a proper rate, such that the cellular redox potential remains at a level compatible with enzymatic reactions. However, this parameter is not only difficult to assess due to its dual compartmentation (mitochondrial and cytosolic) but also because it is well known that most NADH in the cells is bound to the enzymes. In this paper, we investigated the potential relevance of mitochondrial quinones redox state as a marker of mitochondrial metabolism and more particularly mitochondrial redox state. We were able to show that Q2 is an appropriate redox mediator to assess the mitochondrial quinone redox states. On isolated mitochondria, the mitochondrial quinone redox states depend on the mitochondrial substrate and the mitochondrial energetic state (phosphorylating or not phosphorylating). Last but not least, we show that the quinones redox state response allows to better understand the Krebs cycle functioning and respiratory substrates oxidation. Taken together, our results suggest that the quinones redox state is an excellent marker of mitochondrial metabolism. •Cellular energetics if of prime importance in the regulation of cellular functions•Cellular redox potential is difficult to assess due to its dual compartmentation but also because most NADH is bound to the enzymes•We investigated the potential relevance of mitochondrial quinones redox state as a marker of mitochondrial metabolism•The mitochondrial quinones redox state depends on the mitochondrial substrate and the mitochondrial energetic state•The quinones redox state response allows a better understanding of the Krebs cycle functioning and respiratory substrates oxidation