Fig 1: Ctbp2 associates with the ß-catenin destruction complex in ESCs. (a) Using mass spectrometry,35 we identified Ctbp2-interacting proteins that were ß-catenin and core ß-catenin destruction components in ESCs with reasonable peptide counts. (b) Using immunoprecipitation with Flag antibodies from ESCs, showing that Flag-tagged CTBP2 was stably incorporated, and endogenous ß-catenin, Gsk-3ß and Apc were detected with the indicated antibodies. (c) Using immunoprecipitation with Ctbp2 antibodies from wild-type ESCs, endogenous ß-catenin was detected with the indicated antibodies.