Monday 9 January 2006
Band 3 is the major glycoprotein of the erythrocyte membrane and mediates exchange of chloride and bicarbonate across the phospholipid bilayer and plays a central role in respiration of carbon dioxide.
It is a 93,000-Da protein composed of 2 distinct domains that function independently. The 50,000-Da C-terminal polypeptide codes for the transmembrane domain that is involved in anion transport.
The 43,000-Da cytoplasmic domain anchors the membrane cytoskeleton to the membrane through an ankyrin-binding site (band 2.1) and also contains binding sites for hemoglobin and several glycolytic enzymes. Proteins related to red cell band 3 have been identified in several types of nucleated somatic cells.
Peptide mapping shows substantial sequence homology between red cell band 3 protein and a band 3-like protein found in leukocytes (MIM.109280).
germline mutations in
- hereditary stomatocytosis
- autosomal dominant distal renal tubular acidosis (MIM.179800)
- autosomal recessive distal renal tubular acidosis (MIM.602722)
Bruce LJ, Robinson HC, Guizouarn H, Borgese F, Harrison P, King MJ, Goede JS, Coles SE, Gore DM, Lutz HU, Ficarella R, Layton DM, Iolascon A, Ellory JC, Stewart GW. Monovalent cation leaks in human red cells caused by single amino-acid substitutions in the transport domain of the band 3 chloride-bicarbonate exchanger, AE1. Nat Genet. 2005 Nov;37(11):1258-63. PMID: #16227998#