Abstract
Mitochondria are the major site of energy production, derived from proteobacteria that previously involved in an endosymbiotic process with eukaryotic célls. This organelle retained vestiges of its ancestral genome, the mitochondrial circular DNA, which encodes 13 subunit multiprotein complexes of oxidative phosphorylation in the electron transport chain (ETC), while the ETC of other 80 components 80 encoded in nuclear DNA (nDNA). 1400 other proteins that are essential for maintaining the good functioning mitochondria are also encoded in nDNA. Thus, the majority of mitochondrial proteins are translated in the cytoplasm then imported, processed and finalized within the mitochondria. An internal quality control of protein processing, formed by chaperones and proteases that reorganize or degrade defective proteins, is responsible for maintaining mitochondrial proteostasis and ensures the health, not only of the cell, but of the organism as a whole. Mitochondrial unfolded protein response (UPRmt) is a recently discovered control mechanism that realizes disorders in specific proteostasis in mitochondria and performs answers to such stress in a retrograde way, signaling to the nucleus and activating protective genes. This system not only solves the place stress but also has lasting effects on body metabolism, fitness and longevity. It is believed that physical exercise has an important role in the activation of UPRmt, because of important physiological adaptations, as well as its various protective effects, it is important to find out whether this activation actually occurs, what mechanisms are involved in it and how are the molecular adjustments of the involved signaling pathways mediating these responses. Understanding the pathways related to the physiological and pathophysiological changes triggered by UPRmt and fine tune at key points of regulation might aid in the treatment of various diseases triggered by mitochondrial dysfunction, such as metabolic diseases, cancer and neurodegenerative processes.
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