To date, nine genes have been identified in mammals; NHE1-9. These membrane proteins have 10-12 transmembrane domains depending on whether a splice variant is expressed and an intracellular N-terminal. The C-terminal domain can be either intracellular or extracellular, also depending whether a splice variant of the protein is involved. The C-terminal part of the protein also undergoes posttranslational modification such as phosphorylation2. Both NHE-1 and NHE-2 have an extracellular loop which is glycosylated.NHE-2 is detected in the intestine, kidney and parietal cells. It is also detected in skeletal muscle and testis
