Figure 1.

PERK is required for eIF2alpha phosphorylation in S63del nerves. (a) Western blot analysis on P10 to 4-month-old (P120) sciatic nerve lysates was performed for the ER stress marker BiP, P-eIF2alpha, and total eIF2alpha. B-Tubulin (B-Tub) provided the loading control. (b) Protein lysates from liver of WT and Perk+/− animals injected (+) or not (−) with tunicamycin were immunoprecipitated and blotted with an anti-PERK antibody. A lysate from a Perk−/− embryo provided the negative control. PERK*, active form. PERK⁰, inactive form. (c) Immunoprecipitation and western blot for PERK on P28 sciatic nerve extracts. S63del low and high are two different transgenic lines expressing the P0S63del transgene at different levels (60%–210% overexpression, respectively). Densitometric analysis of the active 150 kDa form shows a P0S63del dose-dependent activation of PERK. Calnexin (Cxn) was used as loading control. (d) Western blot analysis for P-eIF2alpha on P28 sciatic nerves; one representative experiment of six is shown. P-eIF2alpha levels were measured by densitometric analysis. Error bars, SEM; *p < .05; by Student’s t test. n = 6. Numbers represent relative molecular weights.