Cell lysis and western blot were performed as described previously (11 (link)). Antibodies used: anti-actin (A5441, Sigma), anti-Phospho-Rb #9308 (Ser807/811) and anti-Rb (4H1) Mouse mAb #9309 (Cell Signaling), anti-β-catenin (sc-7963), anti-Dvl2 (sc-8026, Santa Cruz Biotechnology), and anti-Myc (ab32072, abcam).