In addition to EEF2, two other downregulated phosphoproteins associated with hereditary cerebellar ataxias were identified in FLAG-TTBK2-L209F cells (Table 1): SLC1A3/excitatory amino acid transporter 1, linked with episodic ataxia type 6 through decreased glutamate uptake62; and ATG7, a ubiquitin-activating enzyme E1, implicated in a recessive form of cerebellar ataxia and impaired autophagic flux63. Here, SLC1A3 is linked to aceruloplasminemia.