SLC4A5,7,9 cotransport Na+ with 3HCO3-

Stable Identifier
Reaction [transition]
Homo sapiens
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Members of the SLC4A family couple the transport of bicarbonate (HCO3-) with sodium ions (Na+); they being members 4, 5, 7 and 9. SLC4A5 encodes a protein which is expressed in liver, spleen and testes, with lower levels expressed in parts of the brain and kidney (Sassani et al. 2002). It may have a housekeeping function in regulating the pH of these tissues (Pushkin et al. 2000).

SLC4A7 (aka NBC3, NBCn1) encodes a protein which performs electroneutral cotransport of Na+ and HCO3- with a 1:1 stoichiometry. It is highly expressed in testes and spleen and, to a lesser extent, in many other tissues including heart, muscle, kidney and GI tract (Pushkin et al. 1999).

SLC4A9 (aka AE4) was originally thought to exchange Cl- with HCO3- (hence the name AE4) but this has not been reported. Consensus has emerged that it is indeed a Na+/HCO3- co-transporter (Lipovich et al. 2001). It is predominantly expressed in the kidney, salivary glands, testes, thyroid glands and trachea (Parker et al. 2001).
Literature References
PubMed ID Title Journal Year
11788353 Functional characterization of NBC4: a new electrogenic sodium-bicarbonate cotransporter

Gross, E, Gomer, A, Pushkin, A, Sassani, P, Dukkipati, R, Abuladze, N, Carpenito, G, Kurtz, I

Am J Physiol Cell Physiol 2002
10347222 Cloning, tissue distribution, genomic organization, and functional characterization of NBC3, a new member of the sodium bicarbonate cotransporter family

Newman, D, Pushkin, A, Hwang, J, Abuladze, N, Kurtz, I, Lee, I

J Biol Chem 1999
11305939 A novel sodium bicarbonate cotransporter-like gene in an ancient duplicated region: SLC4A9 at 5q31

King, MC, Lee, MK, Lipovich, L, Lynch, ED

Genome Biol 2001
10978526 Cloning, characterization and chromosomal assignment of NBC4, a new member of the sodium bicarbonate cotransporter family

Newman, D, Pushkin, A, Abuladze, N, Kurtz, I, Xu, G, Lee, I

Biochim Biophys Acta 2000
10362779 Characterization of Na+/HCO-3 cotransporter isoform NBC-3

Soleimani, M, Burnham, CE, Amlal, H

Am J Physiol 1999
Catalyst Activity

sodium:bicarbonate symporter activity of SLC4A5,7,9 [plasma membrane]

Orthologous Events
Cross References
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