Shape and volume changes in erythrocyte ghosts and spectrin-actin networks.

In response to changes in electrolyte concentration and pH, erythrocyte ghosts can exhibit some of the characteristic shapes seen in the intact erythrocyte. These shape changes are accompanied by volume changes; both are reversible, not energy dependent, and not inhibited by sulfhydryl reagents. The volume reduction can also be seen in isolated Triton-free spectrin-actin lattices, showing that this network is capable of reversible contraction. The results suggest that reversible changes in size of the underlying cytoskeleton of the erythrocyte membrane can control cell shape.