CD235a

CD235a, also known as glycophorin A, is a major sialoglycoprotein of the human erythrocyte (red blood cell) membrane. It is the protein product of the GYPA gene and serves as a key erythroid cell surface marker. Glycophorin A is a single-pass type I membrane protein with a heavily glycosylated extracellular domain rich in sialic acid, which contributes to the negative charge and hydration of the red blood cell surface. Its cytoplasmic tail links to the underlying cytoskeleton, helping to maintain membrane integrity during deformation in circulation.

Functionally, glycophorin A provides structural support to the erythrocyte membrane and participates in cell–cell and cell–protein interactions. The extracellular region carries the MN blood group antigens, part of the MNS blood group system, while the protein’s sialylated glycans influence cell surface properties and interactions with other cells and pathogens.

Clinically, CD235a is widely used as a diagnostic marker to identify erythroid lineage cells. It is detected by flow cytometry and immunohistochemistry to characterize red blood cells and to assess erythroid differentiation in bone marrow and hematologic disorders. In pathology, CD235a helps distinguish erythroid precursors from non-erythroid cells and supports classification of myelodysplastic syndromes and acute erythroid leukemias with erythroid differentiation.

In transfusion medicine and blood typing, glycophorin A contributes to MN antigen status, informing compatibility testing. Antibodies targeting CD235a are used for erythroid lineage identification in research and clinical settings.