FUS and amyotrophic lateral sclerosis: Imaging transfected cells using confocal microscopy, it was observed that TDP-43WT and FUSWT remained localised to cell nuclei, while the TDP-43 and FUS mutants mislocalised to the cytoplasm and formed large aggregates and smaller foci, as is observed in ALS patient tissue (Fig. 2b, i and c, i)3,4,50.