Functions both as a transporter that mediates electroneutral anion exchange across the cell membrane and as a structural protein (PubMed:10926824, PubMed:14734552, PubMed:1538405, PubMed:16227998, PubMed:20151848, PubMed:24121512, PubMed:28387307, PubMed:35835865). Component of the ankyrin-1 complex 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 (PubMed:1538405, PubMed:20151848, PubMed:35835865). 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 (PubMed:10926824, PubMed:14734552, PubMed:16227998, PubMed:24121512, PubMed:28387307). ; (Microbial infection) Acts as a receptor for P.falciparum (isolate 3D7) MSP9 and thus, facilitates merozoite invasion of erythrocytes (PubMed:14630931). Acts as a receptor for P.falciparum (isolate 3D7) MSP1 and thus, facilitates merozoite invasion of erythrocytes (PubMed:12692305).