Apc promotes the phosphorylation of Axin in the absence of Wingless stimulation.

<p>(A) Immunoblot of lysates from S2R+ cells treated with dsRNA against indicated genes. Knockdown of Apc or GSK3 results in similar dephosphorylation of Axin. (B) S2R+ cells were treated with <i>white</i> or <i>Apc</i> dsRNAs, followed by the treatment with control medium or Wg CM. Immunoblotting with Axin antibody shows that Wg stimulation induces partial dephosphorylation of Axin, while knockdown of Apc results in further dephosphorylation of Axin in the absence or presence of Wg stimulation. (C) Immunoblot of lysates from third instar larvae expressing indicated transgenes with V5 antibody. Deletion of the Apc-binding domain eliminates the phosphorylated form of Axin-V5. Kinesin was used as a loading control.