TARDBP and proteostasis deficiencies: Our biochemical analysis of human post-mortem brain tissue probed with the novel antiserum verify and expand this finding by demonstrating that phosphorylation of S375 is a consistent feature of pathological TDP-43 species in FTLD–TDP types A–C and ALS–TDP, thereby adding pS375 to the list of validated and confirmed abnormal PTM in TDP-43 proteinopathies.