Fig. 2.

Coarse-grained cytoskeletal dynamics computer simulation. (a) Schematic of cytoskeleton of the human RBC. (b) A minimal physically realistic model with breakable actin–spectrin interaction. A (red sphere) represents an actin protofilament, and B (green and gray spheres) represents a spectrin segment. Only the two ending spectrin units (green spheres) of a spectrin chain can bind to A. (c) Interaction potentials between A–A (steric repulsion), A–B_end (Lennard–Jones potential), A–B_mid (steric repulsion), B–B[1] (spring potential between nearest neighbor spectrin units), and B–B[2] (steric repulsion between any other spectrin units). B_mid represents a nonending spectrin unit, and B_end represents an ending spectrin unit. Note that A–B_end forms breakable linkage. (d) Lipid membrane introduces additional effective repulsion between A–A (12), modeled by a linear potential with cutoff.