Fig. 4. CKII associates with components of the cytoplasmic degradation complex and modulates the ß-catenin-Axin interaction. (A) 293 cells were transiently transfected with Myc-tagged Axin or with Myc-GSK-3ß (empty vectors for control, lanes 1 and 3) and endogenous CKII was immunoprecipitated from comparable amounts of whole-cell lysates. Both Myc-Axin (lane 2) and Myc-GSK-3ß (lane 4) were detected in the immunoprecipitates. (B) HA-tagged wt or Ser/Thr-mutated (single or triple mutation) ß-catenin were transfected together with Myc-tagged Axin into 293 cells. The expression of Myc-Axin was controlled by immunoblot (lanes 4-6). Comparable amounts of Myc-Axin were immunoprecipitated with anti-Myc antibodies and the immunoprecipitates were probed with anti-HA. The association of HA-ß-catenin to Myc-Axin is reduced to an extent that depends on the number of introduced mutations in the CKII consensus motifs (lanes 1-3).