SQSTM1 and amyotrophic lateral sclerosis: Consistently, NP-40–soluble/insoluble protein extraction showed that both ALS- and NEIMY-KIF5A are characterised by poor detergent solubility; however, the former sequestered a larger amount of SQSTM1/p62 protein in the insoluble fraction in comparison to the latter (Fig. 7D).