FIGURE 5.

Proteasomal inhibitor restores arsenic-induced reduction of SLBP protein levels. BEAS-2B cells were treated with 0, 0.1, 0.5, and 1 μm arsenic and with 0.1 μm MG-132 (M) for 48 h. Cells were lysed with radioimmune precipitation assay buffer, and whole-cell lysate was run on 12% SDS acrylamide gels. SLBP protein levels were then measured with anti-SLBP antibody. A, representative Western blot of SLBP levels. B, quantification of SLBP protein levels. Relative protein levels were calculated based on band intensity measured with ImageJ software. Statistical significance was calculated using an unpaired, two-tailed t test with * indicating a p value less than 0.05, ** indicating a p value less than 0.01 for arsenic versus control (C), and # indicating a p value less than 0.5 for arsenic versus arsenic + MG-132. Error bars represent S.D.