TNF-α induces the expression of c-Jun, JunB and c-Fos, but not other Jun or Fos proteins. MCF7 cells were serum starved for 24 h and treated with TNF-α (20 ng/ml) for indicated periods of time. Nuclear protein samples were harvested for Western blot analyses to determine the protein levels of c-Jun, JunB, c-Fos (A), Fra-1, Fra-2, JunD (B) and Ser73-phosphorylated-c-Jun (p-c-Jun; C). The protein levels of β-actin were assessed simultaneously in each group as a loading control. Immunoblots are representative of three separate experiments.