PDBsum entry: 2z6h

Cell adhesion

PDB id: 2z6h

Contents

Protein chain

533 a.a. *

Waters ×28

* Residue conservation analysis

PDB id:

2z6h

Name:

Cell adhesion

Title:

Crystal structure of beta-catenin armadillo repeat region and its c-terminal domain

Structure:

Catenin beta-1. Chain: a. Fragment: armadillo repeat region and c-terminal domain (unp residues 138-781). Synonym: beta-catenin. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.20Å R-factor: 0.213 R-free: 0.249

Authors:

Y.Xing,K.Takemaru,J.Liu,J.Zheng,R.Moon,W.Xu

Key ref:

Y.Xing et al. (2008). Crystal structure of a full-length beta-catenin. Structure, 16, 478-487. PubMed id: 18334222 DOI: 10.1016/j.str.2007.12.021

Date:

01-Aug-07 Release date: 12-Feb-08

Protein chain

P35222  (CTNB1_HUMAN) -  Catenin beta-1

Seq: 781 a.a.

Struc: 533 a.a.

 Gene Ontology (GO) functional annotation 

• Biochemical function: binding (1 term)

DOI no: 10.1016/j.str.2007.12.021

Structure 16:478-487 (2008)

PubMed id: 18334222

Crystal structure of a full-length beta-catenin.

Y.Xing, K.Takemaru, J.Liu, J.D.Berndt, J.J.Zheng, R.T.Moon, W.Xu.

ABSTRACT

beta-catenin plays essential roles in cell adhesion and Wnt signaling, while deregulation of beta-catenin is associated with multiple diseases including cancers. Here, we report the crystal structures of full-length zebrafish beta-catenin and a human beta-catenin fragment that contains both the armadillo repeat and the C-terminal domains. Our structures reveal that the N-terminal region of the C-terminal domain, a key component of the C-terminal transactivation domain, forms a long alpha helix that packs on the C-terminal end of the armadillo repeat domain, and thus forms part of the beta-catenin superhelical core. The existence of this helix redefines our view of interactions of beta-catenin with some of its critical partners, including ICAT and Chibby, which may form extensive interactions with this C-terminal domain alpha helix. Our crystallographic and NMR studies also suggest that the unstructured N-terminal and C-terminal tails interact with the ordered armadillo repeat domain in a dynamic and variable manner.

Selected figure(s)

Figure 2.
Figure 2. Interactions between β-Catenin C-Terminal Domain and Central Armadillo Repeat Domain
(A) Electrostatic surface of the β-catenin armadillo repeat domain covered by the β-catenin C-terminal domain. Residues from the armadillo repeat domain are labeled in black. β-catenin C-terminal domain is in a stick model labeled in red. Key residues of the C-terminal domain interacting with the armadillo repeat domain are highlighted in green for hydrophobic interactions and yellow for charge-charge interactions.
(B) Sequence alignment of the β-catenin C-terminal domain with CLUSTALW. Invariant residues are labeled with stars in red, strongly similar residues are labeled with (:) in green, and weakly similar residues are labeled with (.) in blue. Sequences of the C-terminal domain visible in the β-catenin-R1C crystal structure are framed. The conserved hydrophobic residues (L674, L678, and L682) that docked the helix C into the armadillo repeat domain are marked with arrows.
(C) Ligplot presentation of interactions between β-catenin residues in the C-terminal domain (purple) and the armadillo repeat domain (red). Hydrogen bonds and charge-charge interactions are designated with green dashed lines and distance in Å. A red starburst together with a red dashed line represents hydrophobic interactions.

Figure 4.
Figure 4. The Role of Helix C in β-Catenin Protein-Protein Interactions
(A) Potential interactions between β-catenin helix C and ICAT. β-catenin-R1C (βcat-R1C, cyan) is superimposed onto β-catenin/ICAT (βcat/ICAT, yellow and magenta), based on the Cα's of β-catenin armadillo repeats 10–12 (residues 563–663).
(B) Helix C is unlikely to affect the interaction between the phophorylated E-cadherin and β-catenin armadillo repeats. β-catenin-R1C (βcat-R1C, cyane) is superimposed with β-catenin/phospho-Ecadherin (βcat/pEcad, yellow and red, PDB code: 1I7W) based on all twelve armadillo repeats.
(C) The helix C is required for β-catenin to interact with Chibby. Purified MBP-Chibby protein was immobilized to amylose beads; purified β-catenin and β-catenin fragments were tested for their binding to immobilized MBP-Chibby. The total input and bound β-catenin and β-catenin fragments were visualized by Western blot.

The above figures are reprinted by permission from Cell Press: Structure (2008, 16, 478-487) copyright 2008.

Figures were selected by an automated process.