BSND: Functions as a beta-subunit for CLCNKA and CLCNKB chloride channels. In the kidney CLCNK/BSND heteromers mediate chloride reabsorption by facilitating its basolateral efflux. In the stria, CLCNK/BSND channels drive potassium secretion by recycling chloride for the basolateral SLC12A2 cotransporter. Defects in BSND are the cause of Bartter syndrome type 4A (BS4A); also known as infantile Bartter syndrome with sensorineural deafness. BS refers to a group of autosomal recessive disorders characterized by impaired salt reabsorption in the thick ascending loop of Henle with pronounced salt wasting, hypokalemic metabolic alkalosis, and varying degrees of hypercalciuria. BS4A is associated with sensorineural deafness.

Protein type: Membrane protein, integral; Membrane protein, multi-pass; Transporter; Transporter, ion channel

Chromosomal Location of Human Ortholog: 1p32.1

Cellular Component: basolateral plasma membrane; integral to plasma membrane; plasma membrane; protein complex

Molecular Function: chloride channel activity; voltage-gated chloride channel activity

Disease: Bartter Syndrome, Type 4a