Alpha 1(E)-catenin is an actin-binding and -bundling protein mediating the attachment of F-actin to the membrane adhesion complex.

Abstract

Calcium-dependent homotypic cell-cell adhesion, mediated by molecules such as E-cadherin, guides the establishment of classical epithelial cell polarity and contributes to the control of migration, growth, and differentiation. These actions involve additional proteins, including a-and ,B-catenin (or plakoglobin) and p120, as well as linkage to the cortical actin cytoskeleton. The molecular basis for these interactions and their hierarchy of interaction remain controversial. We demonstrate a direct interaction between Factin and a(E)-catenin, an activity not shared by either the cytoplasmic domain of E-cadherin or 1-catenin. Sedimentation assays and direct visualization by transmission electron microscopy reveal that ai(E)-catenin binds and bundles Factin in vitro with micromolar affinity at a catenin/G-actin monomer ratio of -1:7 (mol/mol). Recombinant human ,B-catenin can simultaneously bind to the a-catenin/actin complex but does not bind actin directly. Recombinant fragments encompassing the amino-terminal 228 residues of al(E)-catenin or the carboxyl-terminal 447 residues individually bind actin in cosedimentation assays with reduced affinity compared with the full-length protein, and neither fragment bundles actin. Except for similarities to vinculin, neither region contains sequences homologous to established actin-binding proteins. Collectively these data indicate that a1(E)-catenin is a novel actin-binding and -bundling protein and support a model in which ac(E)-catenin is responsible for organizing and tethering actin filaments at the zones of E-cadherin-mediated cell-cell contact.

Histopathological, Molecular, and Genetic Profile of Hereditary Diffuse Gastric Cancer: Current Knowledge and Challenges for the Future

“…CTNNA1 encodes the protein -E-catenin, which functions in a complex with -catenin where it binds the cytoplasmic domain of E-cadherin to the cytoskeleton [36,37]. -E-catenin inhibition has been shown to destabilize adherens junctions, weakening the interaction between cells [38].…”

α-Catulin, a Rho signalling component, can regulate NF-κB through binding to IKK-β, and confers resistance to apoptosis

“…a-Catenin has been proposed to modulate actin polymerization states locally at cadherin-mediated cell-cell junctions Yamada et al, 2005). Furthermore, a-catenin itself can directly bind to actin filaments (Rimm et al, 1995). In a-catulin, the amphipathic helices corresponding to the N-terminal region of a-catenin have binding sites for b-catenin, a-actinin, and vinculin, and are conserved.…”

Similar and differential behaviour between the nectin‐afadin‐ponsin and cadherin‐catenin systems during the formation and disruption of the polarized junctional alignment in epithelial cells

“…The cytoplasmic region of cadherin interacts with peripheral membrane proteins, including a-, b-and g-catenins (Ozawa et al 1989;Nagafuchi et al 1991;Tsukita et al 1992). a-Catenin interacts directly with actin ®lament (F-actin) (Rimm et al 1995) and indirectly with it through a-actinin and vinculin, other F-actin-binding proteins (Knudsen et al 1995;Watabe-Uchida et al 1998;Weiss et al 1998). The cadherin-catenin system plays essential roles in the formation and maintenance of cell-cell AJs (Takeichi 1988(Takeichi , 1991Gumbiner 1996).…”