Solute carrier family 26 member 9 (SLC26A9)

Solute carrier family 26 member 9 (SLC26A9) is an epithelial anion transporter and channel, expressed primarily in the lung, stomach, and gastrointestinal epithelium[1][2][3]. It contributes to airway surface hydration and gastric acid production and can operate as a chloride channel, chloride/bicarbonate exchanger, or sodium/anion cotransporter, depending on cellular conditions[2][3][4]. SLC26A9 interacts functionally with the cystic fibrosis transmembrane conductance regulator (CFTR) and is considered a therapeutic target in cystic fibrosis due to its role in airway chloride conductance[1][3][4][5]. It is involved in maintaining ion homeostasis and mucosal protection in epithelia, and its dysfunction or altered regulation is implicated in several diseases affecting fluid balance, notably as a disease modifier in cystic fibrosis[1][3][4][5]. The transporter demonstrates tissue-specific regulation and polymodal transporter/channel function, distinguishing it from other SLC26 family members[1][2].\n\nKey structural features include a STAS (sulfate transporter and anti-sigma factor antagonist) domain, which mediates interaction with CFTR and functional modulation[1][4]. SLC26A9's transport activity is primarily selective for monovalent anions, with high affinity for chloride, low permeability for bicarbonate and sulfate, and demonstrates rapid, possibly channel-like kinetics, though it operates by an alternate-access transporter mechanism rather than a conventional channel[1]. It does not yet have established pharmacological modulators in clinical use, but its proven and potential role in pulmonary and gastric diseases makes it a prime research target in epithelial transport disorders[1][2][3].

Other names

SLC26A9Anion transporter/exchanger protein 9anion transporter/exchanger-9solute carrier family 26 (anion exchanger), member 9

Modulation of anion channel or transporter activity (e.g., promoting chloride conductance or inhibiting exchange activity)