To determine the effects of FUS on ER–mitochondria associations, we quantified ER–mitochondria contacts in NSC34 motor neuron cells transfected with either enhanced green fluorescent protein (EGFP) control vector, EGFP‐FUS or familial ALS mutants EGFP‐FUSR521C or EGFP‐FUSR518K. Here, FUS is linked to amyotrophic lateral sclerosis.