Fig. 4.

Taxol treatment activates the NCS-1-degrading protease calpain. (A) Addition of the calpain inhibitor AK295 prevents Taxol (800 ng/ml, 6 h)-induced reduction of the response amplitude in DRGs and neuroblastoma cells. (B) Western blot analysis reveals that AK295 also prevents the reduction in NCS-1 immunoreactivity. (C) Normalized NCS-1 immunoreactivity is significantly reduced in Taxol-treated cells but not in cells incubated with 10 μM AK295 (n = 3). (D) NCS-1 is cleaved by μ-calpain. Addition of EDTA or the calpain inhibitors ALLN or AK295 prevents NCS-1 cleavage by μ-calpain. NS, not significant; ∗, P < 0.05.