Cytoskeleton mediated effective elastic properties of model red blood cell membranes

TL;DR

This study models the red blood cell membrane as an elastic sheet with a dynamic cytoskeletal network, revealing how cytoskeleton dynamics influence the membrane's elastic properties and fluctuation behavior.

Contribution

It introduces a dynamic coarse-grained model that explicitly accounts for cytoskeletal filament breaking, reconnection, and anchor motion, advancing prior static models.

Findings

Cytoskeleton dynamics significantly affect membrane elasticity.

Simulation results align with experimental fluctuation data.

Mean-field percolation explains the fluctuation behavior.

Abstract

The plasma membrane of human red blood cells consists of a lipid bilayer attached to a regular network of underlying cytoskeletal polymers. We model this system at a dynamic coarse-grained level, treating the bilayer as an elastic sheet and the cytoskeletal network as a series of phantom entropic springs. In contrast to prior simulation efforts, we explicitly account for dynamics of the cytoskeletal network, both via motion of the protein anchors that attach the cytoskeleton to the bilayer and through breaking and reconnection of individual cytoskeletal filaments. Simulation results are explained in the context of a simple mean-field percolation model and comparison is made to experimental measurements of red blood cell fluctuation amplitudes.