Western blot analysis of the MAP kinase proteins ERK1/2, JNK1/2, and p38 in butyrate-treated K562 cells.

Cells were treated with butyrate for the various times indicated and harvested, and 20μg cell lysate was subjected to SDS-gel electrophoresis. After electroblotting, blots were incubated with specific antibodies against phosphorylated ERK1/2, JNK1/2, and p38, respectively, and detected by chemiluminescence. Blots were stripped and reprobed with antibodies against ERK1/2, JNK1/2, and p38, referred to as total in the figure. A shows blots of the butyrate-sensitive subline K562s. B shows blots of the butyrate-resistant subline K562r. Each experiment was repeated 4 times and similar results were obtained.