Cellular extracts (20 μg) from HeLa (A) and HEK 293(B) were subjected to SDS/PAGE, transferred to nitrocellulose membrane and immunoblotted with anti-GST-MSK1 at a concentration of 1 μg/ml. Binding of the primary antibody was detected using rabbit peroxidase conjugated anti- sheep IgG antibody (1 in 10, 000 dilution, Pierce) followed by enhanced chemiluminescence (ECL, Amersham).