Sodium/Hydrogen Exchanger 4 (NHE4)

Organelles of the secretory and endocytic pathways are distinguished by their luminal acidity, which is generated by the activity of an electrogenic vacuolar-type hydrogen ATPase. Progressive acidification of vesicles in the endocytic pathway is essential for the redistribution and degradation of internalized membrane proteins, such as ligand receptor complexes and fluid-phase solutes. SLC9A4 plays a role in maintaining the cation homeostasis and function of the trans-Golgi network.

Szpirer et al. (1994) used human/mouse somatic cell hybrids to map the NHE4 gene to chromosome 2. By analysis of an interspecific backcross panel, Pathak et al. (1996) mapped the homologous gene, Slc9a4, to the proximal region of mouse chromosome 1 where it cosegregates with Slc9a2.