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Titolo:
Biology of the 2Na(+)/1H(+) antiporter in invertebrates
Autore:
Ahearn, GA; Mandal, PK; Mandal, A;
Indirizzi:
Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA Univ Hawaii Manoa Honolulu HI USA 96822 Dept Zool, Honolulu, HI 96822 USA
Titolo Testata:
JOURNAL OF EXPERIMENTAL ZOOLOGY
fascicolo: 4, volume: 289, anno: 2001,
pagine: 232 - 244
SICI:
0022-104X(20010401)289:4<232:BOT2AI>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
NA+-H+ EXCHANGER; BORDER-MEMBRANE-VESICLES; ECHINODERM GASTROINTESTINAL EPITHELIUM; SODIUM-PROTON EXCHANGE; ESCHERICHIA-COLI; BRUSH-BORDER; HOMARUS-AMERICANUS; MOLECULAR-CLONING; CA2+ TRANSPORT; INTRACELLULAR PH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Ahearn, GA Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA Univ Hawaii Manoa Honolulu HI USA 96822 Honolulu, HI 96822 USA
Citazione:
G.A. Ahearn et al., "Biology of the 2Na(+)/1H(+) antiporter in invertebrates", J EXP ZOOL, 289(4), 2001, pp. 232-244

Abstract

The functional expression of membrane transport proteins that are responsible for exchanging sodium and protons is a ubiquitous phenomenon. Among vertebrates the Na+/H+ antiporter occurs in plasma membranes of polarized epithelial cells and non-polarized cells such as red blood cells, muscle cells,and neurons, and in each cell type the transporter exchanges one sodium for one hydrogen ion, is inhibited by amiloride, and regulates intracellular pH and sodium concentration within tight limitations. In polarized epithelial cells this transporter occurs in two isoforms, each of which is restricted to either the brush border or basolateral cell membrane, and perform someswhat different tasks in the two locations. In prokaryotic cells, sodium/proton exchange occurs by an electrogenic 1Na(+)/2H(+) antiporter that is coupled to a primary active proton pump and together these two proteins are capable of tightly regulating the intracellular concentrations of these cations in cells that may occur in environments of 4 M NaCl or pH 10-12; Invertebrate epithelial cells from the gills, gut, and kidney also exhibit electrogenic sodium/proton exchange, but in this instance the transport stoichiometry is 2Na(+)/1H(+). As with vertebrate electroneutral Na+/H+ exchange, the invertebrate transporter is inhibited by amiloride, but because of the occurrence of two external monovalent cation binding sites, divalent cations are able to replace external sodium and also be transported by this system. As a result, both calcium and divalent heavy metals, such as zinc and cadmium, are transported across epithelial brush border membranes in these animals and subsequently undergo a variety of biological activities once accumulated within these cells. Absorbed epithelial calcium in the crustacean hepatopancreas may participate in organismic calcium balance during the molt cycle and accumulated heavy metals may undergo complexation reactions with intracellular anions as a detoxification mechanism. Therefore, while the basic process of sodium/proton exchange may occur in invertebrate cells, the presence of the electrogenic 2Na(+)/1H(+) antiporter in these cells allows them to perform a wide array of functions without the need to develop and express additional specialized transport proteins. (C) 2001 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 15:40:51