Cell or tissue lysates are a useful control for the western blotting application. A source that can be rich in endogenously expressed proteins, this lysate is convenient to use and provided in a denatured format allowing for immediate loading onto an SDS-PAGE gel. HeLa (human epitheloid carcinoma) cells, were grown to 80-90% confluency, then treated with 25 µg/mL anisomycin, an antibiotic and protein synthesis inhibitor, for 15 minutes at 37°C. Anisomycin has been established as a potent activator of the p38/JNK MAPK pathway.