MAPT and amyotrophic lateral sclerosis: Post-mortem studies of ALS/PDC brains revealed evidence of nitrative and oxidative stress [88,89], polyproteinopathy (tau, α-synuclein, TDP-43 and sparse β-amyloid) [90,91], disturbance of protein homeostasis pathways (ubiquitin–proteasome system and the autophagy–lysosome pathway) [92], and activation of the unfolded protein response [93].