Role of Band 3 in the Erythrocyte Membrane Structural Changes Under Isotonic and Hypotonic Conditions

Abstract

An attempt was made to discuss and connect various modeling approaches which have been proposed in the literature in order to shed further light on the erythrocyte membrane relaxation under isotonic and hypotonic conditions. Roles of the main membrane constituents: (1) the actin‐spectrin cortex, (2) the lipid bilayer, and (3) the transmembrane protein band 3 and its course‐consequence relations were considered to estimate the membrane relaxation phenomena. Cell response to loading conditions includes the successive sub‐bioprocesses: (1) erythrocyte local or global deformation, (2) the cortex‐bilayer coupling, and (3) the rearrangements of band 3. The results indicate that the membrane structural changes include: (1) the spectrin flexibility distribution and (2) the rate of its changes influenced by the number of band 3 molecules attached to spectrin filaments, and phosphorylation of the actin‐spectrin junctions. Band 3 rearrangement also influences: (1) the effective bending modulus and (2) the band 3‐bilayer interaction energy and on that base the bilayer bending state. The erythrocyte swelling under hypotonic conditions influences the bilayer integrity which leads to the hemolytic hole formation. The hemolytic hole represents the excited cluster of band 3 molecules.