This locus encodes a sodium bicarbonate cotransporter. The encoded transmembrane protein appears to transport sodium and bicarbonate ions in a 1:1 ratio, and is thus considered an electroneutral cotransporter. The encoded protein likely plays a critical role in regulation of intracellular pH involved in visual and auditory sensory transmission. Alternatively spliced transcript variants encoding distinct isoforms have been described. [provided by RefSeq, Apr 2012],
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Function:
Domain:The PDZ-binding motif mediates interaction with the CFTR, SLC9A3R1/EBP50 complex and probably with USH1C.,enzyme regulation:Transporter activity is regulated by CA2/carbonic anhydrase 2, cAMP and PKA. Insensitive to stilbene derivatives. PubMed:10347222 states it is inhibited by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA).,Function:Electroneutral sodium- and bicarbonate-dependent cotransporter with a Na(+):HCO3(-) 1:1 stoichiometry. Regulates intracellular pH and may play a role in bicarbonate salvage in secretory epithelia. May also have an associated sodium channel activity.,PTM:N-glycosylated.,similarity:Belongs to the anion exchanger (TC 2.A.31) family.,subcellular location:Also described at the apical cell membrane. Localizes to the stereocilia of cochlear outer hair cells and to the lateral membrane of cochlear inner hair cells.,subunit:Interacts with CFTR through SLC9A3R1/EBP50. Interacts with USH1C. Forms a complex with ATP6V1B1 and SLC9A3R1/EBP50. Interacts in a pH dependent-manner with CA2/carbonic anhydrase 2.,tissue specificity:Highly expressed in testis and spleen. Also expressed in retina, colon, small intestine, ovary, thymus, prostate, muscle, heart and kidney. Isoform 1 is expressed in skeletal muscle and heart muscle.,
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Cellular Localization:
Basolateral cell membrane; Multi-pass membrane protein. Apical cell membrane ; Multi-pass membrane protein . Cell projection, stereocilium . Also described at the apical cell membrane. Localizes to the stereocilia of cochlear outer hair cells and to the lateral membrane of cochlear inner hair cells (By similarity). .
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Tissue Expression:
Highly expressed in testis and spleen. Also expressed in retina, colon, small intestine, ovary, thymus, prostate, muscle, heart and kidney. Isoform 1 is expressed in skeletal muscle and heart muscle.