Figure 8. Puromycin treatment leads to increased levels of polyubiquitinated proteins.

293-K^b cells were treated for 4 hours with media alone, 20 µM MG132, or the indicated concentrations of cycloheximide and puromycin (µM). Lysates were subjected to Western blotting with FK2 (upper panel), a monoclonal antibody specific for mono- and polyubiquitinated protein conjugates. Beta-tubulin was probed as a loading control (lower panel). Results are representative of three independent experiments.