Band 3

• OMIM: 109270
• UniProt: P02730

The anion exchanger 1 (AE1 ) (also: band 3 ) is a protein in the cell membrane of red blood cells and nephrons which catalyzes the transport of anions, in particular chloride and bicarbonate from, or in the cell. Thus AE1 is a regulator of acid -base balance in the blood and urine. Other types of tissue with AE1 are hepatocytes, skin epithelium, alveoli of the lung, lymphocytes, neurons and fibroblasts. Mutations in the SLC4A1 gene are responsible for the ( rare ) hereditary forms of ball -cell anemia, elliptocytosis and renal tubular acidosis.

The transport equation is:

The substrate also glucose and water is accepted: AE1 provides more than 90 percent of glucose transport in erythrocytes.

AE1 is responsible for the blood group systems Diego, Swann and Froese protein. AE1 is also the precursor of the senescent - cell antigen, a protein that is present on the membrane of aging cells and is recognized by the immune system. AE1 binds to MSP1 and is the portal of entry for the malaria parasite Plasmodium falciparum. There are polymorphisms in the AE1 promoter that affect the severity of malarial disease.