GYPB
Description
The GYPB (glycophorin B (MNS blood group)) is a protein-coding gene located on chromosome 4.
Glycophorin B (MNS blood group) (gene designation GYPB), also known as sialoglycoprotein delta and SS-active sialoglycoprotein, is a protein that in humans is encoded by the GYPB gene. GYPB has also recently been designated CD235b (cluster of differentiation 235b).
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 (Sta); also Dantu, Sat, Henshaw (He or MNS6), Mg and deletion variants Ena, S-s-U- and Mk. Most of these are the result of gene recombinations between GYPA and GYPB.
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. The gene has 97% sequence homology with the glycophorin A gene from the 5' UTR approximately 1 kilobase upstream from the exon encoding the transmembrane regions to the portion of the coding sequence encoding the first 45 amino acids. There is a signal sequence of 19 amino acid residues. The leader peptide differs by one amino acid and the next 26 amino acids are identical.
GYPB is also known as CD235b, GPB, GYP, GYPA, MNS, PAS-3, SS.
