Tight control of mitochondrial membrane potential by cytochrome c oxidase

• DOI: 10.1016/j.mito.2010.12.004
• Publication Date: 2010-12-14T10:46:13Z
• Authors: Consiglia Pacelli; Dominga Latorre; Tiziana Cocco; Ferdinando Capuano; Christian Kukat; Peter Seibel; Gaetano Villani
• Keywords: Electron Transport Complex IV; 0301 basic medicine; 03 medical and health sciences; Oxygen Consumption; Humans; Cell Line; Membrane Potentials; Mitochondria

In the present work we have critically examined the use of the KCN-titration technique in the study of the control of the cellular respiration by cytochrome c oxidase (COX) in the presence of the mitochondrial membrane potential (Δψ(mito)) in HepG2 cells. We clearly show that the apparent high inhibition threshold of COX in the presence of maximal Δψ(mito) is due to the KCN-induced decrease of Δψ(mito) and not to a low control of COX on the mitochondrial respiration. The tight control exerted by COX on the Δψ(mito) provides further insights for understanding the pathogenetic mechanisms associated with mitochondrial defects in human neuromuscular degenerative disorders.