Sodium–hydrogen antiporter 3

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]

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 74,121,457 bp[2] End 74,169,442 bp[2]
RNA expression pattern More reference expression data
Gene ontology Molecular function • GO:0001948 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 • cell membrane • brush border membrane • brush border • apical plasma membrane • vesicle Biological process • regulation of pH • hydrogen ion 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: 74.12 – 74.17 Mb
PubMed search	[3]	[4]
Wikidata
View/Edit Human View/Edit Mouse

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]