Fig. 5.

The tyrosine kinase inhibitor piceatannol inhibits Aβ-induced activation of ERK and p38 MAPK. THP1 monocytes were pretreated for 1 hr with 50 μg/ml piceatannol or an equal amount of DMSO (final concentration, 70 mm) and then exposed to 50 μm Aβ25–35 for 2 min. A, Activation of ERK2 was demonstrated by Western blot analysis of RIPA lysates (50 μg of protein) using anti-phospho-ERK polyclonal antibodies (top panel). The blots were reprobed with anti-ERK antibody (bottom panel). B, Activation of p38 MAPK was assessed by immunoprecipitation of tyrosine phosphoproteins using monoclonal anti-phosphotyrosine antibodies (PY20) and Western blot analysis using anti-phospho-p38 MAPK antibodies.