8.A.60 The Transmembrane protein 139 (TMEM139) Family
Human kidney anion exchanger 1 (kAE1) mediates Cl-/HCO3- exchange at the basolateral membrane of acid-secreting alpha-intercalated cells. Mutations in the SLC4A1 gene, encoding kAE1 (TC# 2.A.31.1.1), are associated with distal renal tubular acidosis (dRTA). Several studies have shown that impaired trafficking of the mutant kAE1 is an important molecular mechanism underlying the pathogenesis of dRTA. TMEM139 interacts with kAE1. Suppression of endogenous TMEM139 by small interfering RNA (siRNA) and over-expression of TMEM139 in HEK293T cells reduced and increased membrane localization of kAE1, respectively (Nuiplot et al. 2015). Thus, TMEM139 interacts with kAE1 and promotes its intracellular trafficking.