Dynamics of the Actin Cytoskeleton at Adhesion Complexes

Abstract

The shape of cells is altered to allow cells to adapt to their changing environments, including responding to internally generated and externally applied force. Force is sensed by cell surface adhesion proteins that are enriched in sites where cells bind to the extracellular matrix (focal adhesions) and neighboring cells (cell–cell or adherens junctions). Receptors at these adhesion sites stimulate intracellular signal transduction cascades that culminate in dramatic changes in the actin cytoskeleton. New actin filaments form, and/or new and existing filaments can be cleaved, branched, or bundled. Here, we discuss the actin cytoskeleton and its functions. We will examine the current understanding for how the actin cytoskeleton is tethered to adhesion sites. Finally, we will highlight recent studies describing how the actin cytoskeleton at these adhesion sites is remodeled in response to force.

Real-time monitoring of epithelial barrier function by impedance spectroscopy in a microfluidic platform

“…For example, tight junctions can participate in the regulation of the mechanical properties of epithelial monolayers and are finely tuned by the contractility of the actomyosin cytoskeleton, 52 a highly dynamic structure that is sensitive to shear stress. 53 Actomyosin contractility is required both to allow claudins fibrils to operate correctly, and to reinforce the actin cytoskeleton to prevent leaks. 52…”

MCell4 with BioNetGen: A Monte Carlo Simulator of Rule-Based Reaction-Diffusion Systems with Python Interface

“…MCell4 does not currently support the definition of spatially extended complexes that could be useful, for instance, when modeling the post-synaptic density [5] or actin filament networks [38] where simply replacing these polymers with a single point in space is inadequate. Furthermore, the ability to model MCell4 with BioNetGen volume exclusion by individual molecules and complexes will be an important goal for the future.…”

Cell Architecture-Dependent Constraints: Critical Safeguards to Carcinogenesis

“…Among those, the actomyosin cortex lying under the plasma membrane resists external mechanical stresses, and its local activity drives diverse changes in cell shape, including mitotic cell rounding, cytokinetic furrow ingression, cell body retraction during migration, apical constriction and alterations of epithelial thickness [ 11 , 12 ]. Actomyosin stress fibres can be connected to integrin-mediated focal adhesions (FAs) at their ends (ventral stress fibres) and promote rear constriction during cell migration, or they can be positioned above the nucleus to regulate nuclear shape and to convey forces to it [ 19 ], while actomyosin circumferential belts underlying cadherin-mediated Ajs act as direct linkers between adjacent cells to control intercellular surface tension [ 20 ].…”