Diverse transport modes by the solute carrier 26 family of anion transporters

The solute carrier 26 (SLC26) transporters are anion transporters with diverse substrate specificity. Several members are ubiquitous while others show limited tissue distribution. They are expressed in many epithelia and to the extent known, play a central role in anion secretion and absorption. Members of the family are primarily Cl- transporters, although some members transport mainly SO42-, Cl-, HCO3- or I-. A defining feature of the family is their functional diversity. Slc26a1 and Slc26a2 function as specific SO42- transporters while Slc26a4 functions as an electroneutral Cl-/I-/HCO3- exchanger. Slc26a3 and Slc26a6 function as coupled electrogenic Cl-/HCO3- exchangers or as bona fide anion channels. SLC26A7 and SLC26A9 function exclusively as Cl- channels. This short review discusses the functional diversity of the SLC26 transporters.