5y04
From Proteopedia
Crystal Structure of the complex between the vinculin D1 domain and alphaE-catenin
Structural highlights
Function[VINC_MOUSE] Actin filament (F-actin)-binding protein involved in cell-matrix adhesion and cell-cell adhesion. Regulates cell-surface E-cadherin expression and potentiates mechanosensing by the E-cadherin complex. May also play important roles in cell morphology and locomotion (By similarity).[UniProtKB:P18206][1] [CTNA1_MOUSE] 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.[2] Publication Abstract from PubMedMechanotransduction by alpha-catenin facilitates the force-dependent development of adherens junctions (AJs) by recruiting vinculin to reinforce actin anchoring of AJs. The alpha-catenin mechanotransducing action is facilitated by its force-sensing device region that autoinhibits the vinculin-binding site 1 (VBS1). Here, we report the high-resolution structure of the force-sensing device region of alpha-catenin, which shows the autoinhibited form comprised of helix bundles E, F and G. The cryptic VBS1 is embedded into helix bundle E stabilized by direct interactions with the autoinhibitory region forming helix bundles F and G. Our molecular dissection study showed that helix bundles F and G are stable in solution in each isolated form, whereas helix bundle E that contains VBS1 is unstable and intrinsically disordered in solution in the isolated form. We successfully identified key residues mediating the autoinhibition and produced mutated alpha-catenins that display variable force sensitivity and autoinhibition. Using these mutants, we demonstrate both in vitro and in vivo that, in the absence of this stabilization, the helix bundle containing VBS1 would adopt an unfolded form, thus exposing VBS for vinculin binding. We provide evidence for importance of mechanotransduction with the intrinsic force sensitivity for vinculin recruitment to adherens junctions of epithelial cell sheets with mutated alpha-catenins. The force-sensing device region of alpha-catenin is an intrinsically disordered segment in the absence of intramolecular stabilization of the autoinhibitory form.,Hirano Y, Amano Y, Yonemura S, Hakoshima T Genes Cells. 2018 Mar 15. doi: 10.1111/gtc.12578. PMID:29542234[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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