Loss of Tob1 does not change Smad activation. (A) Smad1, Smad5, and Smad8 mRNA was measured by real-time PCR in the liver of Tob1-null (KO) and WT (WT) mice at different times after hepatectomy (n = 3; *, P = 0.001) and increased Smad8 expression at 24 h (n = 3; **, P = 0.01). Each point represents at least three mice. (B) Total and phosphorylated Smad 1/5/8 protein was measured by immunoblot in nuclear extracts of Tob1-null mice. β-Actin and histone H3 immunoblots demonstrate purity of the nuclear extracts and serve as a loading control. All lanes are the most representative of three separate animals.