Proteasome activity assay by proteasome sensor plasmidKKU-055 and KKU-213A were seeded at 1× 10 5 into a 4-well chamber slide. After seeding overnight, the cells were transiently transfected with pZsProsenso-1 plasmid using TurboFect transfection reagent in OptiMEM according to the manufacturer’s protocol.