The importance of PGC-1α in these processes is underscored by observations of PGC-1α KO mice, which exhibit many defects including obesity, neurodegeneration, cardiomyopathy, and heightened sensitivity to ROS (Lin et al., 2004; St-Pierre et al., 2006). Here, PPARGC1A is linked to obesity due to melanocortin 4 receptor deficiency.