The Mitochondrial Unfolded Protein Response: Role in Cellular Homeostasis and Disease.

Mitochondria are the sole semiautonomous organelles of the human cell and play a very important role in not only energy production but also in apoptosis, metabolism and cell signaling. They are also known to be major producers of ROS and RNS free radicals during ATP production. These free radicals in excessive amount may damage the mitochondrial DNA as well as proteome resulting in accumulation of misfolded proteins which may prove deleterious to their functioning and are known to be involved in disease pathology. To maintain healthy proteome, mitochondria have developed as quality control machinery in semiautonomous manner, where cellular proteins such as proteases and heat shock proteins are used for quality control. The present review discusses various aspects of mitochondrial protein quality control operating at outer or inner membrane as well as intermembranal space. The various pathways involved in mitochondrial unfolded protein response have been discussed along with their implications in cancer and various neurodegenerative diseases.