4igg | pdb_00004igg
Full-length human alpha-catenin crystal structure
Structural highlights
Function[CTNA1_HUMAN] Associates with the cytoplasmic domain of a variety of cadherins. The association of catenins to cadherins produces a complex which is linked to the actin filament network, and which seems to be of primary importance for cadherins cell-adhesion properties. Can associate with both E- and N-cadherins. Originally believed to be a stable component of E-cadherin/catenin adhesion complexes and to mediate the linkage of cadherins to the actin cytoskeleton at adherens junctions. In contrast, cortical actin was found to be much more dynamic than E-cadherin/catenin complexes and CTNNA1 was shown not to bind to F-actin when assembled in the complex suggesting a different linkage between actin and adherens junctions components. The homodimeric form may regulate actin filament assembly and inhibit actin branching by competing with the Arp2/3 complex for binding to actin filaments. May play a crucial role in cell differentiation. Publication Abstract from PubMedThe F-actin-binding cytoskeletal protein alpha-catenin interacts with beta-catenin-cadherin complexes and stabilizes cell-cell junctions. The beta-catenin-alpha-catenin complex cannot bind F-actin, whereas interactions of alpha-catenin with the cytoskeletal protein vinculin appear to be necessary to stabilize adherens junctions. Here we report the crystal structure of nearly full-length human alpha-catenin at 3.7-A resolution. alpha-catenin forms an asymmetric dimer where the four-helix bundle domains of each subunit engage in distinct intermolecular interactions. This results in a left handshake-like dimer, wherein the two subunits have remarkably different conformations. The crystal structure explains why dimeric alpha-catenin has a higher affinity for F-actin than does monomeric alpha-catenin, why the beta-catenin-alpha-catenin complex does not bind F-actin, how activated vinculin links the cadherin-catenin complex to the cytoskeleton and why alpha-catenin but not inactive vinculin can bind F-actin. Dimer asymmetry defines alpha-catenin interactions.,Rangarajan ES, Izard T Nat Struct Mol Biol. 2013 Feb;20(2):188-93. doi: 10.1038/nsmb.2479. Epub 2013 Jan, 6. PMID:23292143[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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