Potassium and mitochondria

Abstract

Mitochondria have been recognized for their multifunctional roles in energy transduction, ion transport, signaling, and cell death. Mitochondrial dysfunctions lead to various neurodegenerative disorders and mitochondrial diseases, including Parkinson's disease, Alzheimer's disease, and brain/spinal cord ischemia. It has been observed that potassium flux through the inner mitochondrial membrane regulates the concentration of reactive oxygen species, affects the mitochondrial volume, and changes both the mitochondrial membrane potential and the transport of calcium into the mitochondria. In recent years, a number of potassium channels present in the inner mitochondrial membrane have been described. These findings include an ATP-regulated potassium channel, a large-conductance Ca2+-regulated potassium channel, an intermediate-conductance Ca2+-regulated potassium channel, a voltagegated potassium channel, and a twin-pore domain potassium channel. However, our understanding of the structure of mitochondrial potassium channels is still limited. Additionally, it has been shown that activation of mitochondrial potassium channels protects against both necrotic and apoptotic cell death during myocardial infarction or cerebral hypoxia. These results stimulated an intensive study of the pharmacology of mitochondrial potassium channels and contributed to the development of many hypotheses concerning the role of potassium influx to the mitochondrial matrix in cell death.