Glycophorin A and Band 3 (GPA and AE1)

Glycophorin A and Band 3 are the two most abundant integral membrane proteins of human erythrocytes. Band 3 (SLC4A1/AE1) is a major anion transporter responsible for chloride/bicarbonate exchange critical to CO₂ transport in the blood, and also contributes to membrane structural stability by interacting with the red cell cytoskeleton. Glycophorin A (GPA) is a heavily glycosylated protein that contributes to the erythrocyte surface glycocalyx and prevents red cell aggregation. GPA is essential for efficient band 3 maturation and cell-surface expression, and together with Band 3, defines several clinically significant blood group antigens (notably, the Wright antigen). Defects or polymorphisms in either can result in hemolytic diseases, altered blood group phenotypes, and influence susceptibility to certain infections including malaria[2][3][1][4].

Other names

GPACD235aM/N antigen proteinAnion exchange protein 1AE1SLC4A1Diego blood group antigen protein

Inhibitors (e.g., DIDS, SITS) block chloride/bicarbonate exchange by binding to Band 3 conferring anti-transport effects Antibodies targeting GPA or Band 3 (transfusion medicine, experimental therapeutics): induce cell lysis, block parasite entry, or tag cells for destruction