Sodium–hydrogen antiporter

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Sodium–hydrogen antiporter

The sodium–hydrogen antiporter or sodium–proton exchanger (Na+/H+ exchanger or NHX) is a membrane protein that transports Na+ into the cell, and H+ out of the cell (antiport).

Quick Facts Na+/H+ antiporter 1, Identifiers ...
Na+/H+ antiporter 1
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Identifiers
SymbolNa_H_antiport_1
PfamPF06965
InterProIPR004670
TCDB2.A.36
OPM superfamily106
OPM protein1zcd
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
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Function

They are found in the membranes of many cells, and especially in those of the nephron of the kidney, specifically in the intercalary cells of the collecting duct and in the epithelial cells of the proximal convoluted tubule. The membrane pump is primarily responsible for maintaining homeostasis of pH and sodium.[1] Defects in Na+/H+ antiporters may result in heart or kidney failure.[2] Angiotensin II upregulates this antiporter in the proximal convoluted tubule in order to promote Na+ reabsorption and H+ secretion. Na+/H+ exchangers are thought to be implicated in other disorders such as hypertension. In one study, transgenic mice over expressing this membrane protein were shown to have increased reabsorption and retention of sodium after increased salt intake.[3]

In dopamine receptor signalling,[4] the widely expressed Na+/H+ exchanger NHE-1 is activated downstream of the D2,[5] D3,[6][7] and D4 receptors.[8]

Isoforms

There are several isoforms of the antiporter:

Families

There are several families of sodium/proton antiporters that facilitate the exchange of sodium ions with protons across the lipid membrane. Some of them include:[9]

References

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