Figure 5.

Increased levels of pS421-htt through blockade of PP1 and PP2A protects against NMDA-induced cell death. A, Striatal neurons from YAC128 and WT mice at 10 DIV were treated with 100 and 500 μm NMDA, 30 μm glycine for 10 min in the presence or absence of 100 nm OA. After drug removal, neurons were cultured for 5 h. Neurons were processed to visualize nuclear morphology by DAPI stain. The arrows indicate condensed nuclei. Scale bar, 40 μm. B, Striatal neurons were stimulated with 500 μm NMDA, as described in A and cultured for 15 min. Protein lysates were processed for immunoprecipitation of htt and separation of htt alleles by Western blot. Membranes were probed with Abs against pS421-htt and total htt (mAb 2166) followed by probing with secondary Abs. C, The number of condensed nuclei (white arrows) was determined for each genotype and treatment and expressed relative to the total number of cells in three independent experiments. *p < 0.05, **p < 0.005, ***p < 0.0005 compared within genotype, and ^#p < 0.05 and ^###p < 0.0005 compared between genotypes by t test. Error bars denote ±SEM.