SLC4A4

Electrogenic sodium bicarbonate cotransporter 1 is a membrane transport protein that in humans is encoded by the SLC4A4 gene.

Function

Sodium bicarbonate cotransporters (NBCs) mediate the coupled movement of sodium and bicarbonate ions across the plasma membrane of many cells. This is an electrogenic process with an apparent stoichiometry of 3 bicarbonate ions per sodium ion. Sodium bicarbonate cotransport is involved in bicarbonate secretion/absorption and intracellular pH regulation. Romero and Boron (1999) reviewed NBCs. Soleimani and Burnham (2000) reviewed NBCs and their regulation in physiologic and pathophysiologic states.[supplied by OMIM]

Clinical significance

NBCe1 may participate in regulation of brain extracellular space pH. Some mutations in NBCe1 have been associated with Familial hemiplegic migraine. Other NBCe1 mutations disrupt kidney bicarbonate transport and cause proximal renal tubular acidosis.

Splice variants

NBCe1-A aka kNBC1 (mainly expressed in the kidney)

NBCe1-B aka pNBC1 (expressed in the pancreas and elsewhere)

NBCe1-C (expressed in the brain)

Distribution

The renal SLC4A4 gene product NBCe1-A is specifically expressed in the basolateral membranes of proximal tubule epithelia.

See also

• Solute carrier family

Further reading

This article incorporates text from the United States National Library of Medicine, which is in the public domain.