Glycophorin A (GA-R2)

Glycophorins A (GPA) and B (GPB) are major sialoglycoproteins of the human erythrocyte membrane which bear the antigenic determinants for the MN and SU blood groups. Glycophorins span the membrane and present their amino-terminal end to the extracellular surface of the human erythrocyte. The genetic array of expressed glycophorin surface antigens on erythrocytes defines the blood group phenotype of the individual. GPA is the carrier of blood group M and N specificities, while GPB accounts for S and U specificities. GPA and GPB provide the cells with a large mucin-like surface and it has been suggested this provides a barrier to cell fusion thus minimizing aggregation between red blood cells in the circulation. Anti-glycophorin A has been used to characterize erythroid cell development and in the diagnosis of erythroid leukemias.1-4