Key downstream component of the canonical Wnt signaling pathway (By similarity). In the absence of Wnt, forms a complex with AXIN1, AXIN2, APC, CSNK1A1 and GSK3B that promotes phosphorylation on N-terminal Ser and Thr residues and ubiquitination of CTNNB1 via BTRC and its subsequent degradation by the proteasome. In the presence of Wnt ligand, CTNNB1 is not ubiquitinated and accumulates in the nucleus, where it acts as a coactivator for transcription factors of the TCF/LEF family, leading to activate Wnt responsive genes (By similarity). Involved in the regulation of cell adhesion, as component of an E-cadherin:catenin adhesion complex (By similarity). Acts as a negative regulator of centrosome cohesion. Involved in the CDK2/PTPN6/CTNNB1/CEACAM1 pathway of insulin internalization. Blocks anoikis of malignant kidney and intestinal epithelial cells and promotes their anchorage-independent growth by down-regulating DAPK2. Disrupts PML function and PML-NB formation by inhibiting RANBP2-mediated sumoylation of PML (By similarity). Promotes neurogenesis by maintaining sympathetic neuroblasts within the cell cycle. Involved in chondrocyte differentiation via interaction with SOX9: SOX9-binding competes with the binding sites of TCF/LEF within CTNNB1, thereby inhibiting the Wnt signaling (By similarity). Two separate complex-associated pools are found in the cytoplasm. The majority is present as component of an E-cadherin/ catenin adhesion complex composed of at least E-cadherin/CDH1 and beta-catenin/CTNNB1, and possibly alpha-catenin/CTNNA1; the complex is located to adherens junctions. The stable association of CTNNA1 is controversial as CTNNA1 was shown not to bind to F-actin when assembled in the complex. Alternatively, the CTNNA1-containing complex may be linked to F-actin by other proteins such as LIMA1. Another cytoplasmic pool is part of a large complex containing AXIN1, AXIN2, APC, CSNK1A1 and GSK3B that promotes phosphorylation on N-terminal Ser and Thr residues and ubiquitination of CTNNB1. Interacts directly with AXIN1; the interaction is regulated by CK2 via BTRC and its subsequent degradation by the proteasome. Interacts directly with AXIN1; the interaction is regulated by CDK2 phosphorylation. Wnt-dependent activation of DVL antagonizes the action of GSK3B. When GSK3B activity is inhibited the complex dissociates, CTNNB1 is dephosphorylated and is no longer targeted for destruction. The stabilized protein translocates to the nucleus, where it binds TCF/LEF-1 family members, BCL9, BCL9L and possibly also RUVBL1 and CHD8. Binds CTNNBIP and EP300. CTNNB1 forms a ternary complex with LEF1 and EP300 that is disrupted by CTNNBIP1 binding. Interacts with TAX1BP3 (via the PDZ domain); this interaction inhibits the transcriptional activity of CTNNB1. Interacts with AJAP1, BAIAP1, CARM1, CTNNA3, CXADR and PCDH11Y. Binds SLC9A3R1. Interacts with GLIS2. Interacts with XIRP1. Interacts with PTPRU (via the cytoplasmic juxtamembrane domain) and with SLC30A9. Interacts with EMD. Interacts with SCRIB. Interacts with TNIK and TCF7L2. Interacts with SESTD1 and TRPC4. Interacts directly with AXIN1; the interaction is regulated by CDK2 phosphorylation of AXIN1. Interacts with CAV1. Interacts with TRPV4. The TRPV4 and CTNNB1 complex can interact with CDH1. Interacts with VCL. Interacts with PTPRJ. Interacts with PKT7. Interacts with NANOS1. Interacts with CDK2, NDRG2, NEK2 and CDK5. Found in a complex composed of MACF1, APC, AXIN1, CTNNB1 and GSK3B. Interacts with PTK6. Interacts with SOX7; this interaction may lead to proteasomal degradation of active CTNNB1 and thus inhibition of Wnt/beta-catenin-stimulated transcription. Identified in a complex with HINT1 and MITF. Interacts with FHIT. The CTNNB1 and TCF4 complex interacts with PML. Interacts with FERMT2. Identified in a complex with TCF4 and FERMT2. Interacts with RAPGEF2. Interacts with FAT1 (via the cytoplasmic domain). Interacts with RORA. May interact with P-cadherin/CDH3. Interacts with RNF220 (By similarity). Interacts with CTNND2 (By similarity). Interacts (via the C-terminal region) with CBY1 (By similarity). The complex composed, at least, of APC, CTNNB1 and GSK3B interacts with JPT1; the interaction requires the inactive form of GSK3B (phosphorylated at 'Ser-9'). Interacts with DLG5 (By similarity). Interacts with FAM53B; promoting translocation to the nucleus. Interacts with TMEM170B (By similarity). Interacts with AHI1 (By similarity). Interacts with GID8 (By similarity). Component of an cadherin:catenin adhesion complex composed of at least of CDH26, beta-catenin/CTNNB1, alpha-catenin/CTNNA1 and p120 catenin/CTNND1 (By similarity). Forms a complex comprising APPL1, RUVBL2, APPL2, HDAC1 and HDAC2 (By similarity). Interacts with IRF2BPL; mediates the ubiquitination and degradation of CTNNB1 (By similarity). Interacts with AMFR (By similarity). Interacts with LMBR1L (By similarity). Interacts with SOX30; prevents interaction of CTNNB1 with TCF7L2/TCF4 and leads to inhibition of Wnt signaling (By similarity). Interacts with SOX9; inhibiting CTNNB1 activity by competing with the binding sites of TCF/LEF within CTNNB1, thereby inhibiting the Wnt signaling (By similarity). Interacts with SPN/CD43 cytoplasmic tail (By similarity). Interacts (when phosphorylated at Tyr-333) with isoform M2 of PKM (PKM2); promoting transcription activation (By similarity). Colocalized with RAPGEF2 and TJP1 at cell-cell contacts (By similarity). Cytoplasmic when it is unstabilized (high level of phosphorylation) or bound to CDH1. Translocates to the nucleus when it is stabilized (low level of phosphorylation). Interaction with GLIS2 and MUC1 promotes nuclear translocation. Interaction with EMD inhibits nuclear localization. The majority of beta-catenin is localized to the cell membrane. In interphase, colocalizes with CROCC between CEP250 puncta at the proximal end of centrioles, and this localization is dependent on CROCC and CEP250. In mitosis, when NEK2 activity increases, it localizes to centrosomes at spindle poles independent of CROCC. Colocalizes with CDK5 in the cell-cell contacts and plasma membrane of undifferentiated and differentiated neuroblastoma cells. Interaction with FAM53B promotes translocation to the nucleus (By similarity). Expressed in the testis. Highly expressed at E30-60 day DPC in the testis. Reduced expression at E90 day DPC. Phosphorylation by GSK3B requires prior phosphorylation of Ser-45 by another kinase. Phosphorylation proceeds then from Thr-41 to Ser-33. Phosphorylated by NEK2. EGF stimulates tyrosine phosphorylation. Phosphorylated on Ser-33 and Ser-37 by HIPK2. This phosphorylation triggers proteasomal degradation. Phosphorylation at Ser-552 by AMPK promotes stabilizion of the protein, enhancing TCF/LEF-mediated transcription. Phosphorylation on Ser-191 and Ser-246 by CDK5. Phosphorylation by CDK2 regulates insulin internalization. Phosphorylation by PTK6 at Tyr-64, Tyr-142, Tyr-331 and/or Tyr-333 with the predominant site at Tyr-64 is not essential for inhibition of transcriptional activity. Phosphorylation by SRC at Tyr-333 promotes interaction with isoform M2 of PKM (PKM2); promoting transcription activation. Ubiquitinated by the SCF(BTRC) E3 ligase complex when phosphorylated by GSK3B, leading to its degradation. Ubiquitinated by a E3 ubiquitin ligase complex containing UBE2D1, SIAH1, CACYBP/SIP, SKP1, APC and TBL1X, leading to its subsequent proteasomal degradation (By similarity). Ubiquitinated and degraded following interaction with SOX9 (By similarity). S-nitrosylation at Cys-619 within adherens junctions promotes VEGF-induced, NO-dependent endothelial cell permeability by disrupting interaction with E-cadherin, thus mediating disassembly adherens junctions. O-glycosylation at Ser-23 decreases nuclear localization and transcriptional activity, and increases localization to the plasma membrane and interaction with E-cadherin CDH1. Deacetylated at Lys-49 by SIRT1. Belongs to the beta-catenin family.