A selective inhibitor of the stress-induced PPP1R15A that does not affect the constitutive PPP1R15B; 50 μM prolongs eIF2α phosphorylation after ER stress, delaying translation which protects cells from misfolded protein-induced cytotoxicity; 1-5 mg/kg prevents defects resulting from protein misfolding in mouse models of amyotrophic lateral sclerosis and Charcot-Marie-Tooth neuropathy