Tightening Red-Cell Membranes

The lipid bilayer model of membrane structure proposed by Davson and Danielli₁remains an attractive, but imperfect, description of erythrocyte membrane conformation. Important modifications have become necessary in this model, which depicts: (a) hydrophobic lipid components (acyl chains of fatty acids and cholesterol) facing toward the middle of the membrane; (b) hydrophilic components (phosphate, carboxyl, and amino groups of phospholipids) oriented outward toward the cytoplasmic and extracellular surfaces; and (c) proteins layered over both outer and inner surfaces, attached to the hydrophilic portions of the lipid bilayer by ionic bonds. It is clear that the Davson-Danielli structure, although possibly present.