Force-dependent changes in alpha-catenin conformation
type: CreativeWork
description: Cadherin complexes are crucial intercellular adhesions that transduce force fluctuations at junctions to activate signals that reinforce stressed intercellular contacts. α-Catenin is an identified force sensor within cadherin complexes. Mechanical force regulates binding of α-catenin to the actin-binding protein vinculin and to the actin cytoskeleton itself. This regulation is accomplished through distinct conformational changes in the α-catenin central modulatory (M) domain and the C-terminal actin-binding domain (ABD), respectively. Force-induced unfurling of the M domain exposes a cryptic vinculin-binding site, resulting in increased vinculin binding under tension. Previous studies found that a cooperative network of salt bridges stabilizes the autoinhibited conformation of the M domain. Studies described in this dissertation established that disruption of salt bridges within the M domain triggers the activation (unfurling) of α-catenin to bind vinculin, both at equilibrium and under tension. These studies compared wild-type (WT) α-catenin to salt-bridge mutants designed to disrupt a key interaction within the salt-bridge network. Binding measurements quantified enhanced vinculin binding by a salt-bridge mutant, allowing the calculation of an equilibrium constant between the autoinhibited and active conformations of α-catenin. Equilibrium molecular dynamics (MD) simulations indicated that disrupting the salt-bridge network destabilizes the autoinhibited conformation of α-catenin. Imaging of live cells expressing a Fӧrster resonance energy transfer (FRET)-based α-catenin conformation sensor demonstrated that salt-bridge disruption promotes α-catenin unfurling under steady-state tension. Furthermore, a constant-force steered molecular dynamics (SMD) simulation of the M domain suggested the adoption of an intermediate conformation during force-induced activation, and identified a novel load-bearing salt bridge within this structure. The mechanism underlying tension-…
abstract: Cadherin complexes are crucial intercellular adhesions that transduce force fluctuations at junctions to activate signals that reinforce stressed intercellular contacts. α-Catenin is an identified force sensor within cadherin complexes. Mechanical force regulates binding of α-catenin to the actin-binding protein vinculin and to the actin cytoskeleton itself. This regulation is accomplished through distinct conformational changes in the α-catenin central modulatory (M) domain and the C-terminal actin-binding domain (ABD), respectively. Force-induced unfurling of the M domain exposes a cryptic vinculin-binding site, resulting in increased vinculin binding under tension. Previous studies found that a cooperative network of salt bridges stabilizes the autoinhibited conformation of the M domain. Studies described in this dissertation established that disruption of salt bridges within the M domain triggers the activation (unfurling) of α-catenin to bind vinculin, both at equilibrium and under tension. These studies compared wild-type (WT) α-catenin to salt-bridge mutants designed to disrupt a key interaction within the salt-bridge network. Binding measurements quantified enhanced vinculin binding by a salt-bridge mutant, allowing the calculation of an equilibrium constant between the autoinhibited and active conformations of α-catenin. Equilibrium molecular dynamics (MD) simulations indicated that disrupting the salt-bridge network destabilizes the autoinhibited conformation of α-catenin. Imaging of live cells expressing a Fӧrster resonance energy transfer (FRET)-based α-catenin conformation sensor demonstrated that salt-bridge disruption promotes α-catenin unfurling under steady-state tension. Furthermore, a constant-force steered molecular dynamics (SMD) simulation of the M domain suggested the adoption of an intermediate conformation during force-induced activation, and identified a novel load-bearing salt bridge within this structure. The mechanism underlying tension-…
author: Barrick, Samantha Kirstin Tieszen
language: en
keywords: Alpha-catenin, Cell adhesion, Protein biophysics
date published: 2018-03-13T15:25:14Z
date modified: 2026-07-22T22:24:37Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/99209