ID:S4A7_HUMAN DESCRIPTION: RecName: Full=Sodium bicarbonate cotransporter 3; AltName: Full=Sodium bicarbonate cotransporter 2; AltName: Full=Sodium bicarbonate cotransporter 2b; Short=Bicarbonate transporter; AltName: Full=Solute carrier family 4 member 7; 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. 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). BIOPHYSICOCHEMICAL PROPERTIES: Kinetic parameters: KM=24 mM for external sodium; 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. INTERACTION: P31946:YWHAB; NbExp=1; IntAct=EBI-1044546, EBI-359815; SUBCELLULAR LOCATION: Basolateral cell membrane; Multi-pass membrane protein. Apical cell membrane; Multi-pass membrane protein (By similarity). Cell projection, stereocilium (By similarity). Note=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). 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. DOMAIN: The PDZ-binding motif mediates interaction with the CFTR, SLC9A3R1/EBP50 complex and probably with USH1C. SIMILARITY: Belongs to the anion exchanger (TC 2.A.31) family.
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
Pfam Domains: PF00955 - HCO3- transporter family PF07565 - Band 3 cytoplasmic domain
SCOP Domains: 55804 - Phoshotransferase/anion transport protein
ModBase Predicted Comparative 3D Structure on Q9Y6M7
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
