The SLC4 family of bicarbonate (HCO3-) transporters

Michael F. Romero, An Ping Chen, Mark D. Parker, Walter F. Boron

Research output: Contribution to journalReview articlepeer-review

176 Scopus citations


The SLC4 family consists of 10 genes (SLC4A1-5; SLC4A7-11). All encode integral membrane proteins with very similar hydropathy plots - consistent with 10-14 transmembrane segments. Nine SLC4 members encode proteins that transport HCO3- (or a related species, such as CO32-) across the plasma membrane. Functionally, eight of these proteins fall into two major groups: three Cl-HCO3 exchangers (AE1-3) and five Na+-coupled HCO3- transporters (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE). Two of the Na +-coupled transporters (NBCe1, NBCe2) are electrogenic; the other three Na+-coupled HCO3- transporters and all three AEs are electroneutral. In addition, two other SLC4 members (AE4, SLC4A9 and BTR1, SLC4A11) do not yet have a firmly established function. Most, though not all, SLC4 members are functionally inhibited by 4,4′-diisothiocyanatostilbene- 2,2′-disulfonate (DIDS). SLC4 proteins play important roles many modes of acid-base homeostasis: the carriage of CO2 by erythrocytes, the transport of H+ or HCO3- by several epithelia, as well as the regulation of cell volume and intracellular pH.

Original languageEnglish (US)
Pages (from-to)159-182
Number of pages24
JournalMolecular Aspects of Medicine
Issue number2-3
StatePublished - Apr 2013


  • Bicarbonate
  • Boron
  • Carbonate
  • Chloride
  • Cotransporter
  • Exchanger
  • SLC4
  • Sodium

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Clinical Biochemistry


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