β-Arrestin2 oligomerization is required for suppressing tau turnover. (A) Representative immunoblots of DIV18 cortical primary neurons from tau P301S transduced with GFP, β-arrestin2 ΔIP6C-GFP, or β-arrestin2 ΔIP6N-GFP at DIV5. (B) Quantification of tau level (n = 4, #P < 0.0001, ***P < 0.0005). (C and D) Representative immunoblots of indicated proteins in HeLa-V5-tau cells transfected with control vector, β-arrestin2 ΔIP6C,and β-arrestin2 ΔIP6N treated with cycloheximide (100 μg/mL) for indicated times. (E) Quantification of tau levels with cycloheximide treatment (n = 4; **P < 0.005, ***P < 0.0005, #P < 0.0001, repeated measures ANOVA, followed by Bonferroni post hoc).