Rsk levels are elevated in HD mouse and cellular models. Rsk1 (A, C and E) and Rsk2 (B, D and F) protein levels were analyzed by western blot of protein extracts obtained from the striatum of 6- and 10-month old wild-type (HdhQ7/Q7) and knock-in (HdhQ111/Q111) mice (A and B), from wild-type (STHdhQ7/Q7) and mutant (STHdhQ111/Q111) htt knock-in striatal cells (C and D), and from the striatum of 8- and 12-week old WT and R6/1 mice (E and F). Htt protein levels were also analyzed by western blot in knock-in models (A-D). Results (mean ± SEM; n = 4-6) represent the ratio between Rsk and actin levels obtained by densitometric analysis of western blot data, and are expressed as a percentage of HdhQ7/Q7 levels at 6 months (A and B), as a percentage of protein levels in STHdhQ7/Q7 cells (C and D), or as a percentage of protein levels in WT mice at 8 weeks (E and F). Data were analyzed by two-way ANOVA followed by Bonferroni's post hoc test (A, B, E and F) or by Student's t-test (C and D). *p < 0.05 and **p < 0.01 as compared with HdhQ7/Q7 mice (A and B), **p < 0.01 and ***p < 0.001 as compared with STHdhQ7/Q7 cells (C and D), and *p < 0.05 and **p < 0.01 as compared with WT mice (E and F). Representative immunoblots are presented.