This entry represents a domain found in the C-terminal of the solute carrier family 12 (SLC12) members, which are K-Cl cotransporters. The SLC12 family members are predicted to have 12 transmembrane (TM) regions in a central hydrophobic domain, together with hydrophilic N- and C-termini that are likely cytoplasmic. Comparison of their sequences with those of other ion-tranporting membrane proteins reveals that they are part of a new superfamily of cation-chloride co-transporters, which includes the Na-Cl and Na-K-2Cl co-transporters.