Mitochondrial membrane potential

The mitochondrial membrane potential (Delta psi m) generated by proton pumps (Complexes I, III and IV) is an essential component in the process of energy storage during oxidative phosphorylation. Together with the proton gradient (Delta pH), Delta psi m forms the transmembrane potential of hydrogen ions which is harnessed to make ATP. The levels of Delta psi m and ATP in the cell are kept relatively stable although there are limited fluctuations of both these factors that can occur reflecting normal physiological activity. However, sustained changes in both factors may be deleterious. A long-lasting drop or rise of Delta psi m vs normal levels may induce unwanted loss of cell viability and be a cause of various pathologies. Among other factors, Delta psi m plays a key role in mitochondrial homeostasis through selective elimination of dysfunctional mitochondria. It is also a driving force for transport of ions (other than H+) and proteins which are necessary for healthy mitochondrial functioning. We propose additional potential mechanisms for which Delta psi m is essential for maintenance of cellular health and viability and provide recommendations how to accurately measure Delta psi m in a cell and discuss potential sources of artifacts. (C) 2017 Published by Elsevier Inc.