PGC-1α-mediated regulation of mitochondrial function and physiological implications.

The majority of human energy metabolism occurs in skeletal muscle mitochondria emphasizing the importance of understanding the regulation of myocellular mitochondrial function. The transcriptional co-activator peroxisome proliferatoractivated receptor gamma coactivator 1 alpha (PGC-1 alpha) has been characterized as a major factor in the transcriptional control of several mitochondrial components. Thus, PGC-1 alpha is often described as a master regulator of mitochondrial biogenesis as well as a central player in regulating the antioxidant defense. However, accumulating evidence suggests that PGC-1 alpha is also involved in the complex regulation of mitochondrial quality beyond biogenesis, which includes mitochondrial network dynamics and autophagic removal of damaged mitochondria. In addition, mitochondrial reactive oxygen species production has been suggested to regulate skeletal muscle insulin sensitivity, which may also be influenced by PGC-1 alpha. This review aims to highlight the current evidence for PGC-1 alpha-mediated regulation of skeletal muscle mitochondrial function beyond the effects on mitochondrial biogenesis as well as the potential PGC-1 alpha-related impact on insulin-stimulated glucose uptake in skeletal muscle. Novelty PGC-1 alpha regulates mitochondrial biogenesis but also has effects on mitochondrial functions beyond biogenesis. Mitochondrial quality control mechanisms, including fission, fusion, and mitophagy, are regulated by PGC-1 alpha. PGC-1 alpha-mediated regulation of mitochondrial quality may affect age-related mitochondrial dysfunction and insulin sensitivity.