FIG. 3.

Arsenite inhibits activation of ERK1,2. Human skin fibroblasts were treated with arsenite (80 μM) for indicated periods of time. Thereafter, cells were lysed and the levels of phosphorylated ERK1,2 (p-ERK1,2), JNK (p-JNK), and p38 (p-p38) were determined by Western blot analysis with phospho-specific antibodies. Protein loading was studied with antibodies against total p38 and ERK1,2. The cellular levels of catalytic subunits for PP1 and PP2A were determined by Western blot analysis with specific antibodies.