SOD1 and amyotrophic lateral sclerosis: Notably, SOD1-G93A/PGC-1α double transgenic animals showed a similar level of complex I (Figure 4A, B) and complex IV activities (Figure 4C, D) as wild-type animals, suggesting that the presence of PGC-1α attenuated the mitochondrial ETC transport defect in mutant ALS animals.