Functions both as a transporter that mediates electroneutral anion exchange across the cell membrane and as a structural protein. Major integral membrane glycoprotein of the erythrocyte membrane; required for normal flexibility and stability of the erythrocyte membrane and for normal erythrocyte shape via the interactions of its cytoplasmic domain with cytoskeletal proteins, glycolytic enzymes, and hemoglobin. Functions as a transporter that mediates the 1:1 exchange of inorganic anions across the erythrocyte membrane. Mediates chloride-bicarbonate exchange in the kidney, and is required for normal acidification of the urine. Phenyl isothiocyanate inhibits anion transport in vitro. A dimer in solution, but in its membrane environment, it exists primarily as a mixture of dimers and tetramers and spans the membrane asymmetrically. Interacts (via cytoplasmic N-terminal domain) with ANK1 (via N-terminal ANK repeats); tetramer formation is critical for ankyrin association. Interacts with STOM. Isoform 2 interacts with TM139 (PubMed:26049106). (Microbial infection) Interacts (via N-terminus) with P.falciparum (isolate K1) aldolase FBPA; the interaction inhibits FBPA catalytic activity. Detected in the erythrocyte cell membrane and on the basolateral membrane of alpha-intercalated cells in the collecting duct in the kidney. Detected in erythrocytes (at protein level). Expressed in kidney (at protein level). Phosphorylated on Tyr-8 and Tyr-21 most likely by SYK. PP1-resistant phosphorylation that precedes Tyr-359 and Tyr-904 phosphorylation. Phosphorylated on Tyr-359 and Tyr-904 most likely by LYN. PP1-inhibited phosphorylation that follows Tyr-8 and Tyr-21 phosphorylation. N-glycosylated. SLC4A1 is responsible for the Diego blood group system [MIM:110500]. The molecular basis of the Di(a)=Di1/Di(b)/Di2 blood group antigens is a single variation in position 854; Leu-854 corresponds to Di(a) and Pro-854 to Di(b). The molecular basis of the Wr(a)=Di3/Wr(b)/Di4 blood group antigens is a single variation in position 658; Lys-658 corresponds to Wr(a) and Glu-658 to Wr(b). The blood group antigens Wd(a)=Di5 (Waldner-type) has Met-557; Rb(a)=Di6 has Leu-548 and WARR=Di7 has Ile-552. SLC4A1 is responsible for the Swann blood group system (SW) [MIM:601550]. Sw(a+) has a Gln or a Trp at position 646 and Sw(a-) has an Arg. SLC4A1 is responsible for the Froese blood group system (FR) [MIM:601551]. FR(a+) has a Lys at position 480 and FR(a-) has a Glu. Genetic variations in SLC4A1 are involved in resistance to malaria [MIM:611162]. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting distinct genetic loci, including the gene represented in this entry. Belongs to the anion exchanger (TC 2.A.31) family. Band 3 entry Blood group antigen gene mutation database