1qz7

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1qz7, resolution 2.20Å ()
Gene: CTNNB1 (Homo sapiens), AXIN (Xenopus laevis)
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Contents

Beta-catenin binding domain of Axin in complex with beta-catenin

Publication Abstract from PubMed

The "beta-catenin destruction complex" is central to canonical Wnt/beta-catenin signaling. The scaffolding protein Axin and the tumor suppressor adenomatous polyposis coli protein (APC) are critical components of this complex, required for rapid beta-catenin turnover. We determined the crystal structure of a complex between beta-catenin and the beta-catenin-binding domain of Axin (Axin-CBD). The Axin-CBD forms a helix that occupies the groove formed by the third and fourth armadillo repeats of beta-catenin and thus precludes the simultaneous binding of other beta-catenin partners in this region. Our biochemical studies demonstrate that, when phosphorylated, the 20-amino acid repeat region of APC competes with Axin for binding to beta-catenin. We propose that a key function of APC in the beta-catenin destruction complex is to remove phosphorylated beta-catenin product from the active site.

Crystal structure of a beta-catenin/axin complex suggests a mechanism for the beta-catenin destruction complex., Xing Y, Clements WK, Kimelman D, Xu W, Genes Dev. 2003 Nov 15;17(22):2753-64. Epub 2003 Nov 4. PMID:14600025

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Disease

[CTNB1_HUMAN] Defects in CTNNB1 are associated with colorectal cancer (CRC) [MIM:114500]. Note=Activating mutations in CTNNB1 have oncogenic activity resulting in tumor development. Somatic mutations are found in various tumor types, including colon cancers, ovarian and prostate carcinomas, hepatoblastoma (HB), hepatocellular carcinoma (HCC). HBs are malignant embryonal tumors mainly affecting young children in the first three years of life. Defects in CTNNB1 are a cause of pilomatrixoma (PTR) [MIM:132600]; a common benign skin tumor.[1][2][3] Defects in CTNNB1 are a cause of medulloblastoma (MDB) [MIM:155255]. MDB is a malignant, invasive embryonal tumor of the cerebellum with a preferential manifestation in children.[4][5] Defects in CTNNB1 are a cause of susceptibility to ovarian cancer (OC) [MIM:167000]. Ovarian cancer common malignancy originating from ovarian tissue. Although many histologic types of ovarian neoplasms have been described, epithelial ovarian carcinoma is the most common form. Ovarian cancers are often asymptomatic and the recognized signs and symptoms, even of late-stage disease, are vague. Consequently, most patients are diagnosed with advanced disease. Note=A chromosomal aberration involving CTNNB1 is found in salivary gland pleiomorphic adenomas, the most common benign epithelial tumors of the salivary gland. Translocation t(3;8)(p21;q12) with PLAG1. Defects in CTNNB1 may be a cause of mesothelioma malignant (MESOM) [MIM:156240]. An aggressive neoplasm of the serosal lining of the chest. It appears as broad sheets of cells, with some regions containing spindle-shaped, sarcoma-like cells and other regions showing adenomatous patterns. Pleural mesotheliomas have been linked to exposure to asbestos.[6]

Function

[CTNB1_HUMAN] 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.[7][8][9][10] [AXIN1_XENLA] Controls dorsoventral patterning via two opposing effects; down-regulates beta-catenin to inhibit the Wnt signaling pathway and ventralize embryos, but also dorsalizes embryos by activating a Wnt-independent JNK signaling pathway.

About this Structure

1qz7 is a 2 chain structure with sequence from Homo sapiens and Xenopus laevis. Full crystallographic information is available from OCA.

See Also

Reference

  • Xing Y, Clements WK, Kimelman D, Xu W. Crystal structure of a beta-catenin/axin complex suggests a mechanism for the beta-catenin destruction complex. Genes Dev. 2003 Nov 15;17(22):2753-64. Epub 2003 Nov 4. PMID:14600025 doi:10.1101/gad.1142603
  1. Moreno-Bueno G, Gamallo C, Perez-Gallego L, Contreras F, Palacios J. beta-catenin expression in pilomatrixomas. Relationship with beta-catenin gene mutations and comparison with beta-catenin expression in normal hair follicles. Br J Dermatol. 2001 Oct;145(4):576-81. PMID:11703283
  2. van Noort M, van de Wetering M, Clevers H. Identification of two novel regulated serines in the N terminus of beta-catenin. Exp Cell Res. 2002 Jun 10;276(2):264-72. PMID:12027456 doi:10.1006/excr.2002.5520
  3. Chan EF, Gat U, McNiff JM, Fuchs E. A common human skin tumour is caused by activating mutations in beta-catenin. Nat Genet. 1999 Apr;21(4):410-3. PMID:10192393 doi:10.1038/7747
  4. van Noort M, van de Wetering M, Clevers H. Identification of two novel regulated serines in the N terminus of beta-catenin. Exp Cell Res. 2002 Jun 10;276(2):264-72. PMID:12027456 doi:10.1006/excr.2002.5520
  5. Huang H, Mahler-Araujo BM, Sankila A, Chimelli L, Yonekawa Y, Kleihues P, Ohgaki H. APC mutations in sporadic medulloblastomas. Am J Pathol. 2000 Feb;156(2):433-7. PMID:10666372
  6. Shigemitsu K, Sekido Y, Usami N, Mori S, Sato M, Horio Y, Hasegawa Y, Bader SA, Gazdar AF, Minna JD, Hida T, Yoshioka H, Imaizumi M, Ueda Y, Takahashi M, Shimokata K. Genetic alteration of the beta-catenin gene (CTNNB1) in human lung cancer and malignant mesothelioma and identification of a new 3p21.3 homozygous deletion. Oncogene. 2001 Jul 12;20(31):4249-57. PMID:11464291 doi:10.1038/sj.onc.1204557
  7. Lillehoj EP, Lu W, Kiser T, Goldblum SE, Kim KC. MUC1 inhibits cell proliferation by a beta-catenin-dependent mechanism. Biochim Biophys Acta. 2007 Jul;1773(7):1028-38. Epub 2007 Apr 22. PMID:17524503 doi:S0167-4889(07)00092-4
  8. Bahmanyar S, Kaplan DD, Deluca JG, Giddings TH Jr, O'Toole ET, Winey M, Salmon ED, Casey PJ, Nelson WJ, Barth AI. beta-Catenin is a Nek2 substrate involved in centrosome separation. Genes Dev. 2008 Jan 1;22(1):91-105. Epub 2007 Dec 17. PMID:18086858 doi:10.1101/gad.1596308
  9. Li H, Ray G, Yoo BH, Erdogan M, Rosen KV. Down-regulation of death-associated protein kinase-2 is required for beta-catenin-induced anoikis resistance of malignant epithelial cells. J Biol Chem. 2009 Jan 23;284(4):2012-22. doi: 10.1074/jbc.M805612200. Epub 2008, Oct 27. PMID:18957423 doi:10.1074/jbc.M805612200
  10. Fiset A, Xu E, Bergeron S, Marette A, Pelletier G, Siminovitch KA, Olivier M, Beauchemin N, Faure RL. Compartmentalized CDK2 is connected with SHP-1 and beta-catenin and regulates insulin internalization. Cell Signal. 2011 May;23(5):911-9. doi: 10.1016/j.cellsig.2011.01.019. Epub 2011 , Jan 22. PMID:21262353 doi:10.1016/j.cellsig.2011.01.019

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