Erythrocyte membrane structure and function.

The structure and function of the proteins of the human erythrocyte membrane are discussed. The major integral proteins comprise the anion transport protein (band 3), the glucose transporter and four sialic acid-rich polypeptides. The anion transport protein equilibrates Cl- and HCO-3 between the plasma and red cell and also provides an anchorage site for peripheral proteins including those in the red cell cytoskeleton. The sialic acid-rich proteins are predominantly exposed at the surface of the cell. The bulk of the peripheral proteins are organized in a complex fashion to form a skeletal meshwork at the cytoplasmic surface of the membrane which maintains the shape and deformability of the red cell. The changes in membrane components during differentiation of the red cell are discussed.