Mitochondrial sodium/hydrogen exchanger 9B2 (SLC9B2, aka NHA2) is ubiquitously expressed and mediates the electrogenic exchange of 1 Na+ (or 1 Li+) for 2 H+ across the inner mitochondrial membrane (Xiang et al. 2007, Taglicht et al. 1993). This transport is thought to play a role in salt homeostasis and pH regulation in humans.