JUN and amyotrophic lateral sclerosis: According with the maintained differentiation capacity, 3-weeks-old SYT13+/− cultures did not display any significant sign of cellular sufferance: the levels of the autophagy receptor SQSTM1/p62 (Supplementary Fig. 2B), which forms toxic aggregates in ALS MNs [18], as well as the stress marker c-Jun (Supplementary Fig. 2C), whose increased activation is a shared phenotype across the ALS spectrum [13], were indeed comparable to those of SYT13+/+ neurons.