SQSTM1 and amyotrophic lateral sclerosis: This is further suggested by the finding of ALS-linked genes playing a role in protein degradation via either the proteasome (such as UBQLN2) or autophagy (SQSTM1, OPTN, TBK1) [13,59,60,61], as well as by the presence of poly-ubiquitinated proteins in the cytoplasmic inclusions that accumulate in ALS-FTD patient derived cells and cell models [62].