Fig. 3.

IKKβ is required for efficient S13 phosphorylation of ∼350-kDa full-length mouse HTT in liver. Male R6/1 (HD) and NT WT controls, both containing the tamoxifen-inducible Cre and floxed alleles of IKKβ, were treated with tamoxifen or oil vehicle control at week 10 and tissue was taken at week 16 at the completion of the study. IKKβ normalized to loading control ERK1/2 was significantly reduced in liver of HD and NT mice with tamoxifen treatment over oil control in whole-cell lysate (A–C). Anti-HTT phosphoserine 13 (pS13) antibody was used to immunoprecipitate phosphorylated full-length mouse HTT which was then detected by Western blot with anti-total HTT antibody. Levels of pS13-HTT were significantly reduced relative to total HTT with IKKβ knockout in HD and NT controls, while levels of total HTT normalized to ERK1/2 were not affected (A–C). Western images (A and B) were quantitated using Scion software (C). *P < 0.05, ****P < 0.0001 values represent means ± SEM. Statistical significance was determined by paired t test.