Sodium–hydrogen antiporter 3 also known as sodium–hydrogen exchanger 3 (NHE3) or solute carrier family 9 member 3 (SLC9A3) is a protein that in humans is encoded by the SLC9A3 gene.^[5][6]

Quick Facts SLC9A3, Identifiers ...

SLC9A3
Identifiers
Aliases	SLC9A3, NHE3, NHE-3, Sodium–hydrogen antiporter 3, DIAR8, solute carrier family 9 member A3
External IDs	OMIM: 182307 MGI: 105064 HomoloGene: 55804 GeneCards: SLC9A3
Gene location (Human) Chr. Chromosome 5 (human)[1] Band 5p15.33 Start 470,456 bp[1] End 524,449 bp[1]
Gene location (Mouse) Chr. Chromosome 13 (mouse)[2] Band 13 C1|13 40.15 cM Start 74,269,576 bp[2] End 74,317,561 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sural nerve gallbladder body of stomach right uterine tube kidney appendix rectum fundus skin of abdomen stromal cell of endometrium Top expressed in jejunum duodenum kidney large intestine colon secondary oocyte proximal tubule left colon otolith organ utricle More reference expression data BioGPS More reference expression data
Gene ontology Molecular function protein binding PDZ domain binding antiporter activity solute:proton antiporter activity potassium:proton antiporter activity sodium:proton antiporter activity Cellular component integral component of membrane membrane cell surface extracellular exosome plasma membrane brush border membrane brush border apical plasma membrane vesicle Biological process regulation of pH proton transmembrane transport ion transport cation transport sodium ion transport potassium ion transmembrane transport transmembrane transport regulation of intracellular pH sodium ion import across plasma membrane transport anion transmembrane transport Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 6550 105243 Ensembl ENSG00000281861 ENSG00000066230 ENSMUSG00000036123 UniProt P48764 G3X939 RefSeq (mRNA) NM_001284351 NM_004174 NM_001081060 RefSeq (protein) NP_001271280 NP_004165 NP_001074529 Location (UCSC) Chr 5: 0.47 – 0.52 Mb Chr 13: 74.27 – 74.32 Mb PubMed search [3] [4]
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SLC9A3 is a sodium–hydrogen antiporter. It is found on the apical side of the epithelial cells of the proximal tubule of the nephron of the kidney, in the apical membrane of enterocytes of the intestine, as well as the basolateral side of both duodenal and pancreatic cells responsible for the release of HCO−3 into the duodenal lumen. It is primarily responsible for maintaining the balance of sodium. It is also indirectly linked to buffering of blood pH. The NHE3 antiporter imports one sodium ion into the cytosol of a tubule cell as it ejects one hydrogen ion from the cell into the lumen of the proximal tubule. The sodium within the tubule cell may then be retained by the body rather than excreted in the urine. The NHE3 antiporter indirectly contributes to blood buffering capacity because hydrogen ions that are ejected are the products of the carbonic anhydrase enzyme, which also makes bicarbonate.^[7]

Protein kinase C stimulates NHE3, while protein kinase A inhibits it.^[8]

There is a specific protein functioning as an NHE3 regulator, Sodium-hydrogen antiporter 3 regulator 1.

Sodium–hydrogen antiporter 3 has been shown to interact with CHP.^[11]