Mouse 3T3 embryonic cells grown to 85% confluency were harvested, homogenized in modified RIPA buffer, and cleared by centrifugation. Total protein concentration of the lysate was determined using BCA protein assay (BSA was used as a standard). Lysate was mixed with Laemmli Sample Buffer containing reducing reagent and heated for 5 minutes at 90°C. Lysate is supplied as 200 μg in 100 μl per vial (2.0 mg/ml total protein concentration) in 1X Laemmli sample buffer.