SLC4A4 (Electrogenic sodium bicarbonate cotransporter 1) is an electrogenic sodium/bicarbonate cotransporter with a Na(+):HCO3(-) stoichiometry varying from 1:2 to 1:3. It may regulate bicarbonate influx/efflux at the basolateral membrane of cells and regulate intracellular pH. SLC4A4 interacts with carbonic anhydrase 2 and carbonic anhydrase 4 which may regulate transporter activity. There are four named isoforms produced by alternative splicing.


This gene encodes a sodium bicarbonate cotransporter (NBC) involved in the regulation of bicarbonate secretion and absorption and intracellular pH. Mutations in this gene are associated with proximal renal tubular acidosis. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008].