The motor neuron-specific Daxx-p38α extrinsic apoptosis pathway is activated by glycogen synthase kinase-3β (GSK-3β) inhibitor VIII treatment. (a) Proteins from each group were extracted and immunoprecipitated with anti-Fas antibody. The precipitates were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot analysis with anti-Daxx antibody. The Fas-Daxx interaction increased significantly in 1000 nM GSK-3β inhibitor-treated cells. (b) p38α immunoreactivity (IR) is presented in an enhanced chemiluminescence radiograph as quantitative values. Band signal intensity increased nearly threefold in 1000 nM GSK-3β inhibitor VIII-treated cells, compared with that in the control. No differences in IR were detected in the low-dose treated groups compared with the control group.