Inhibitor of the Wnt signaling pathway. Down-regulates beta-catenin. Probably facilitate the phosphorylation of beta-catenin and APC by GSK3B. Interacts with glycogen synthase kinase-3 beta (GSK3B) and beta-catenin. The interaction between axin and beta-catenin occurs via the armadillo repeats contained in beta-catenin. Interacts with SMAD7 and RNF111 (By similarity). Interacts with ANKRD6 (PubMed:12183362). Interacts with SIAH1 (By similarity). Interacts with SIAH2 (By similarity). Expressed in Tcf7-positive innate-like T-cells (at protein level). The tankyrase-binding motif (also named TBD) is required for interaction with tankyrase TNKS and TNKS2. ADP-ribosylated by tankyrase TNKS and TNKS2. Poly-ADP-ribosylated protein is recognized by RNF146, followed by ubiquitination and subsequent activation of the Wnt signaling pathway. Ubiquitinated by RNF146 when poly-ADP-ribosylated, leading to its degradation and subsequent activation of the Wnt signaling pathway. Deubiquitinated by USP34, deubiquitinated downstream of beta-catenin stabilization step: deubiquitination is important Wnt signaling to positively regulate beta-catenin (CTNBB1)-mediated transcription. Probably phosphorylated by GSK3B and dephosphorylated by PP2A.