Potassium Chloride Cotransporters 1 (KCC1)

The full-length sequence was obtained from EST clones and by RT-PCR of HEK293 cell RNA. The 1,085-amino acid KCC1 protein is 24 to 25% identical to NKCC1 and SLC12A3 and shares 97% identity with rabbit KCC1. The overall structure of KCC1 is similar to that of other cation-chloride cotransporters, with 12 predicted transmembrane regions, a large extracellular loop with potential N-linked glycosylation sites, and cytoplasmic N- and C-terminal domains. Northern blot analysis revealed that KCC1 is expressed ubiquitously. KCC1 exhibits the functional properties of the red cell K-Cl cotransporter, including stimulation by swelling and N-ethylmaleimide, and low affinities for rubidium, chloride, and bumetanide.