GYPB

Glycophorin B (MNS blood group) (gene designation GYPB) also known as sialoglycoprotein delta and SS-active sialoglycoprotein is a protein which in humans is encoded by the GYPB gene. GYPB has also recently been designated CD235b (cluster of differentiation 235b).

Function

Glycophorin A (GYPA) and B (GYPB; this protein) are major sialoglycoproteins of the human erythrocyte membrane which bear the antigenic determinants for the MN and Ss blood groups respectively. In addition to the M or N and S or s antigens, that commonly occur in all populations, about 40 related variant phenotypes have been identified. These variants include the Miltenberger (Mi) complex and several isoforms of Stones (St^a); also Dantu, Sat, Henshaw (He or MNS6), Mg and deletion variants En^a, S-s-U- and M^k. Most of these are the result of gene recombinations between GYPA and GYPB.

Genomics

The gene is located on the long arm of chromosome 4 (4q28-q31) and has 5 exons. It was first sequenced in 1987 the peptide sequence of 72 amino acids having been determined earlier that year.