Dynamics of membranes driven by actin polymerization

Abstract

A motile cell, when stimulated, shows a dramatic increase in the activity of its membrane, manifested by the appearance of dynamic membrane structures such as lamellipodia, filopodia and membrane ruffles. The external stimulus turns on membrane bound activators, like Cdc42 and PIP2, which cause increased branching and polymerization of the actin cytoskeleton in their vicinity leading to a local protrusive force on the membrane. The emergence of the complex membrane structures is a result of the coupling between the dynamics of the membrane, the activators and the protrusive forces. We present a simple model that treats the dynamics of a membrane under the action of actin polymerization forces that depend on the local density of freely diffusing activators on the membrane. We show that, depending on the spontaneous membrane curvature associated with the activators, the resulting membrane motion can be wave-like, corresponding to membrane ruffling and actin-waves, or unstable, indicating the tendency of filopodia to form. Our model also quantitatively explains a variety of related experimental observations and makes several testable predictions.

37 pages, 8 figures, revtex

References in corpus (7)

• Nonequilibrium Fluctuations, Travelling Waves, and Instabilities in Active Membranes
• Organization and instabilities of entangled active polar filaments
• Active Membrane Fluctuations Studied by Micropipet Aspiration
• Dynamic Phase Transitions in Cell Spreading
• Growth Velocities of Branched Actin Networks
• Self-organized Pattern Formation in Motor-Microtubule Mixtures
• The internal states of active inclusions and the dynamics of an active membrane

Cited by in corpus (27)

• Stochastic mechano-chemical kinetics of molecular motors: a multidisciplinary enterprise from a physicist's perspective
• Active Contact Forces Drive Non-Equilibrium Fluctuations in Membrane Vesicles
• Effect of interactions on the cellular uptake of nanoparticles
• Activating membranes
• Geometry of wave propagation on active deformable surfaces
• Pattern Formation in Reaction-Diffusion System on Membrane with Mechanochemical Feedback
• Active interface growth and pattern formation in membrane-protein systems
• Protein recruitment through indirect mechanochemical interactions
• Active tuning of synaptic patterns enhances immune discrimination
• A Variational Approach to Particles in Lipid Membranes
• Statistical mechanics of a single active slider on a fluctuating interface
• Actin filaments growing against a barrier with fluctuating shape
• Geometry-induced patterns through mechanochemical coupling
• Kinetic roughening in active interfaces
• Why A Large Scale Mode Can Be Essential For Understanding Intracellular Actin Waves
• Statistical mechanics of an elastically pinned membrane: Equilibrium dynamics and power spectrum
• Universal properties of active membranes
• Stability of patterns on thick curved surfaces
• Generic instabilities in a fluid membrane coupled to a thin layer of ordered active polar fluid
• Interplay between surface and bending energy helps membrane protrusion formation
• Interface growth driven by a single active particle
• Pattern formation, localized and running pulsation on active spherical membranes
• Effect of relative timescale on a system of particles sliding on a fluctuating energy landscape: Exact derivation of product measure condition
• Small deformations of Helfrich energy minimising surfaces with applications to biomembranes
• A Novel Mechanism of Ordering in a Coupled Driven System: Vacancy Induced Phase Separation
• A renormalization group study of the dynamics of active membranes: universality classes and scaling laws
• Spatial organisation of multiple species of active particles interacting with an interface