<p>(A) Co-IP of DKK3b, ß-TrCP and ß-<sup>S33Y</sup>catenin from HEK293 cell lysates. Epitope tagged targets were expressed by transient transfection in HEK293 cells, immune precipitates collected by Protein A/G Sepharose, and co-precipitating partners were analyzed by immunoblot with epitope specific antibodies. (B) Co-IP of HEK293 cell lysates lacking one binding partner. (C) shRNA knockdown of ß-TrCP in HeLa cells. Immunoblots done with anti-TrCP IgG. (D) Effects of <i>ß-TrCP</i> KD and ß-TrCP rescue on TAT-DKK3b dependent inhibition of TOPflash activity in HeLa cells. Unaltered, non-silencing control, <i>ß-TrCP</i> KD cells, and rescued <i>ß-TrCP</i> KD cells expressing a mouse ß-TrCP rescue plasmid were stimulated with ±LiCl for 16h in the absence or presence of TAT-DKK3b (5 μg/ml). TOPflash activity reported as fold change from resting HeLa cells. Data are reported as the means ± se (n = 4); each experiment was repeated 3 times.</p