title: The SLC4 family of bicarbonate (HCO₃⁻) transporters.
abstract: 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 CO3(2-)) 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.
authors.affiliation: Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. romero.michael@mayo.edu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Romero
authors.forename: An-Ping
authors.initials: AP
authors.lastname: Chen
authors.forename: Mark D
authors.initials: MD
authors.lastname: Parker
authors.forename: Walter F
authors.initials: WF
authors.lastname: Boron
mesh_terms: D001639:Bicarbonates / Q000378:metabolism*; D027963:Chloride-Bicarbonate Antiporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004912:Erythrocytes / Q000378:metabolism; D040461:Gene Components; D006801:Humans; D008958:Models, Molecular; D005810:Multigene Family / Q000235:genetics*; D011487:Protein Conformation; D027982:Sodium-Bicarbonate Symporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*
chemical_list: D001639:Bicarbonates; D027963:Chloride-Bicarbonate Antiporters; D027982:Sodium-Bicarbonate Symporters