FUS and amyotrophic lateral sclerosis: This experiment was conducted in HEK293 FUS WT and KO cells first to identify the normal role of FUS in mitochondria of healthy cells, and then in mutant FUS iPSC-derived motor neurons and fibroblasts derived from ALS patients, and autopsy spinal cord tissues from FUS-ALS patients and hFUS*R495X mice38, to unveil the implications in FUS-ALS.