Solute Carrier Family 9, Member 9 (SLC9A9)

SLC9A9 encodes a sodium hydrogen exchanger that is a member of the solute carrier 9 protein family. The encoded protein localizes the to the late recycling endosomes and may play an important role in maintaining cation homeostasis. Defects in this gene are associated with attention-deficit/hyperactivity disorder.The predicted SLC9A9 protein contains 645 amino acids and has a molecular mass of 72.6 kD. Its sequence suggests a membrane-bound protein with 10 transmembrane domains. Northern blot analysis of human adult tissues demonstrated wide expression of SLC9A9, at highest levels in heart and skeletal muscle, followed by placenta, kidney, and liver. Expression of a 3.5-kb transcript in brain was highest in the medulla and spinal cord.