D
IPR006153

Cation/H+ exchanger, transmembrane domain

InterPro entry
Short nameCation/H_exchanger_TM
domain relationships

Description

This entry represents the transmembrane region of a number of cation/proton exchangers, including Na+/H+ exchangers, K+/H+ exchangers and Na+(K+,Li+,Rb+)/H+ exchangers.

Sodium proton exchangers (NHEs) constitute a large family of integral membrane protein transporters that are responsible for the counter-transport of protons and sodium ions across lipid bilayers
[8, 9]
. These proteins are found in organisms across all domains of life. In archaea, bacteria, yeast and plants, these exchangers provide increased salt tolerance by removing sodium in exchanger for extracellular protons. In mammals they participate in the regulation of cell pH, volume, and intracellular sodium concentration, as well as for the reabsorption of NaCl across renal, intestinal, and other epithelia
[10, 4, 5, 6]
. Human NHE is also involved in heart disease, cell growth and in cell differentiation
[7]
. The removal of intracellular protons in exchange for extracellular sodium effectively eliminates excess acid from actively metabolising cells. In mammalian cells, NHE activity is found in both the plasma membrane and inner mitochondrial membrane. To date, nine mammalian isoforms have been identified (designated NHE1-NHE9)
[1, 2]
. These exchangers are highly-regulated (glyco)phosphoproteins, which, based on their primary structure, appear to contain 10-12 membrane-spanning regions (M) at the N terminus and a large cytoplasmic region at the C terminus. The transmembrane regions M3-M12 share identity with other members of the family. The M6 and M7 regions are highly conserved. Thus, this is thought to be the region that is involved in the transport of sodium and hydrogen ions. The cytoplasmic region has little similarity throughout the family. There is some evidence that the exchangers may exist in the cell membrane as homodimers, but little is currently known about the mechanism of their antiport
[3]
.

References

1.Na+/H+ exchangers of mammalian cells. Orlowski J, Grinstein S. J. Biol. Chem. 272, 22373-6, (1997). View articlePMID: 9278382

2.Identification of a mitochondrial Na+/H+ exchanger. Numata M, Petrecca K, Lake N, Orlowski J. J. Biol. Chem. 273, 6951-9, (1998). View articlePMID: 9507001

3.Comparative molecular analysis of Na+/H+ exchangers: a unified model for Na+/H+ antiport? Dibrov P, Fliegel L. FEBS Lett. 424, 1-5, (1998). View articlePMID: 9537504

4.Na+/H+ exchangers in renal regulation of acid-base balance. Bobulescu IA, Moe OW. Semin. Nephrol. 26, 334-44, (2006). View articlePMID: 17071327

5.Alkali cation exchangers: roles in cellular homeostasis and stress tolerance. Pardo JM, Cubero B, Leidi EO, Quintero FJ. J. Exp. Bot. 57, 1181-99, (2006). View articlePMID: 16513813

6.[Structure function and regulation of the mammalian Na+/H+ exchangers] Wakabayashi S. Seikagaku 72, 1329-34, (2000). PMID: 11187762

7.Physiological role and regulation of the Na+/H+ exchanger. Malo ME, Fliegel L. Can. J. Physiol. Pharmacol. 84, 1081-95, (2006). View articlePMID: 17218973

8.The Na+/H+ exchanger gene family. Burckhardt G, Di Sole F, Helmle-Kolb C. J. Nephrol. 15 Suppl 5, S3-21, (2002). PMID: 12027219

9.Multiple modes of regulation of Na+/H+ exchangers. Hayashi H, Szaszi K, Grinstein S. Ann. N. Y. Acad. Sci. 976, 248-58, (2002). PMID: 12502567

10.Na+/H+ exchangers and the regulation of volume. Alexander RT, Grinstein S. 187, 159-67, (2006). PMID: 16734752

GO terms

Contributing Member Database Entry
This website requires cookies, and the limited processing of your personal data in order to function. By using the site you are agreeing to this as outlined in our Privacy Notice and Terms of Use.