Data points are from individual mice and groups of flies. (A–E) WT (w¹¹¹⁸) and PINK1⁵ flies received TZ or vehicle for 10 days beginning on the first day after eclosion. Day 10 assays included: (A) Example of wing posture defect and percentage of w¹¹¹⁸ and PINK1⁵ flies with wing posture defects. n = 6, with 80 flies for each treatment in each trial. (B and C) Example of TH Western blot (B) and quantification of TH (C). n = 5, with 40 fly heads for each treatment in each trial. (D) ATP content in brains (relative to w¹¹¹⁸). n = 3, with 200 fly heads for each treatment in each trial. (E) Climbing behavior of flies. n = 3, with 100 flies for each treatment in each trial. (F) Climbing behavior of LRRK^ex1 male flies. n = 6, with 100 flies for each treatment in each trial. (G–K) TZ administration to mThy1-hSNCA–transgenic mice. (G) Schematic for experiments in panels H–K. (H) Example of Western blot of α-synuclein in striatum and SNc. (I and J) Quantification of α-synuclein in striatum and SNc. n = 5. (K) Duration that mice remained on an accelerating rotarod. n = 5. Data are from individual groups of flies (A–F) and individual mice (I–K). Bars and whiskers indicate the mean ± SEM. Blue indicates controls and red indicates TZ treatment. Supplemental Table 3 shows statistical tests and P values for all comparisons. *P < 0.05, **P < 0.01, and ***P < 0.001, by 1-way ANOVA with Tukey’s test (D) and Kruskal-Wallis with a Dwass-Steele-Critchlow-Fligner test (A–C, E, F, and I–K).