Western blot analysis of extracts from HeLa cells transfected with 20 nM control siRNA #6201 (-) or 2, 5, or 20 nM pool 42 MAPK siRNA, using p44/42 MAP Kinase Antibody #9102 (upper), p38 MAP Kinase Antibody #9212 (middle) and SAPK/JNK (56G8) Rabbit mAb #9258 (lower) in combination with ATP-Citrate Lyase Antibody #4332. The 44/42 MAP Kinase Antibody confirms silencing of p42 MAP Kinase expression, and ATP-Citrate Lyase Antibody is used to control for loading and specificity of pool p42 MAP Kinase siRNA. The experiment also demonstrates specifically that the pool p42 MAPK siRNA does not interfere with the expression of p44 MAPK, p38 MAPK or SAPK/JNKs.