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The Structure of a beta-Catenin Binding Repeat from Adenomatous Polyposis Coli (APC) in Complex with beta-Catenin
Structural highlights
FunctionCTNB1_MOUSE Key downstream component of the canonical Wnt signaling pathway. 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. Involved in the regulation of cell adhesion. 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 (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe adenomatous polyposis coli (APC) tumor suppressor protein plays a critical role in regulating cellular levels of the oncogene product beta-catenin. APC binds to beta-catenin through a series of homologous 15 and 20 amino acid repeats. We have determined the crystal structure of a 15 amino acid beta-catenin binding repeat from APC bound to the armadillo repeat region of beta-catenin. Although it lacks significant sequence homology, the N-terminal half of the repeat binds in a manner similar to portions of E-cadherin and XTcf3, but the remaining interactions are unique to APC. We discuss the implications of this new structure for the design of therapeutics, and present evidence from structural, biochemical and sequence data, which suggest that the 20 amino acid repeats can adopt two modes of binding to beta-catenin. Molecular mechanisms of beta-catenin recognition by adenomatous polyposis coli revealed by the structure of an APC-beta-catenin complex.,Eklof Spink K, Fridman SG, Weis WI EMBO J. 2001 Nov 15;20(22):6203-12. PMID:11707392[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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