PKCι-mediated ERK activation protects cells from expanded polyglutamine-induced cytotoxicity.

<p>A) Western blot analysis of cell extracts from control and siPKCιA transfectants with the phospho-ERK specific antibody. The basal levels of ERK phosphoprotein were significantly reduced in PKCι depleted cells when compared to control RNA transfectants. Total ERK levels were assessed with the pan ERK antibody which also served as a loading control. B) U87MG cells were pre-treated with the MEK inhibitor U0126 for 2 hours prior to transfection with GFP, Htt-25 and Htt-103. Cell survival was assessed by MTT 24 hours post-transfection. Blockade of ERK in Htt-103 expressing cells resulted in a significant reduction in cell survival when compared to untreated Htt-103 expressing cells (* p<0.05). Data are represented as the average of three independent experiments performed in triplicate, with error bars indicating standard error of the mean. C) Western blot analysis of extracts from untreated and U0126 treated U87MG cells expressing Htt-103 with the phospho-ERK antibody confirming the blockade of ERK phosphorylation in U0126 treated cells. Pan-ERK was used to detect total ERK levels and actin served as a loading control.