HOCl-LDL causes phosphorylation of p38 MAPK. (A) Human platelets were activated with 1 and 20 μg/mL HOCl-LDL with or without 1 μM ADP for 30 seconds. Anisomycin-treated C6 glioma cells were a positive control for p38 MAP kinase activation. The activated and total p38 MAPK levels were determined by Western blot analysis using phosphospecific (upper panel) and total anti-p38 MAPK (lower panel) antibodies. (B) Platelets preincubated with the specific PKC inhibitor Bis for 5 minutes at 37°C were stimulated with HOCl-LDL (1 μg/mL, ox-LDL) for 30 seconds. Activated and total p38 MAPK levels were determined by Western blot as in panel A.