Identification of the GSK3β domain required for association with p53. Schematic diagrams (left) depict GSK3β constructs (A) sequentially truncated from the C-terminal, (B) sequentially truncated from the N-terminal, and (C) deletion constructs. GSK3β constructs were transiently transfected into H1299 cells and HA-p53 was inducibly expressed by removing doxycycline from the medium for 24 hr . Cells were subjected to lysis, immunoprecipitation using sheep anti-mouse IgG Dynabeads (Dynal Biotech) and 1 μg anti-HA (Covance) and immunoblotting as indicated. The heavy chain (HC) and light chain (LC) of IgG are indicated, and β-actin was used as loading control.