Finally, the puromycin-sensitive aminopeptidase (PSA) is a predominantly cytoplasmic neuronal enzyme enriched in the brain, identified as a genetic modifier of tau-associated toxicity in model systems, and found to be increased in FTD patient brains, so far suggesting a neuro-protective role in tauopathy and other proteinopathies [90]. Here, MAPT is linked to proteostasis deficiencies.