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Titolo:
THE EPITHELIAL INWARD RECTIFIER CHANNEL KIR7.1 DISPLAYS UNUSUAL K+ PERMEATION PROPERTIES
Autore:
DORING F; DERST C; WISCHMEYER E; KARSCHIN C; SCHNEGGENBURGER R; DAUT J; KARSCHIN A;
Indirizzi:
MAX PLANCK INST BIOPHYS CHEM,DEPT MEMBRANE BIOPHYS,AM FASSBERG 11 D-37070 GOTTINGEN GERMANY MAX PLANCK INST BIOPHYS CHEM,DEPT MEMBRANE BIOPHYS D-37070 GOTTINGEN GERMANY UNIV MARBURG,INST NORMAL & PATHOL PHYSIOL D-35037 MARBURG GERMANY
Titolo Testata:
The Journal of neuroscience
fascicolo: 21, volume: 18, anno: 1998,
pagine: 8625 - 8636
SICI:
0270-6474(1998)18:21<8625:TEIRCK>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
RECTIFYING POTASSIUM CHANNEL; GUINEA-PIG HEART; 2 PORE DOMAINS; FUNCTIONAL EXPRESSION; TEA BLOCKADE; RAT-BRAIN; REGION; IRK1; ION; RECTIFICATION;
Keywords:
INWARDLY RECTIFYING; CHOROID PLEXUS; KIR7.1; PORE LOOP; IN SITU HYBRIDIZATION; BA2+ BLOCK;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
60
Recensione:
Indirizzi per estratti:
Citazione:
F. Doring et al., "THE EPITHELIAL INWARD RECTIFIER CHANNEL KIR7.1 DISPLAYS UNUSUAL K+ PERMEATION PROPERTIES", The Journal of neuroscience, 18(21), 1998, pp. 8625-8636

Abstract

Rat and human cDNAs were isolated that both encoded a 360 amino acid polypeptide with a tertiary structure typical of inwardly rectifying K channel (Kir) subunits. The new proteins, termed Kir7.1, were <37% identical to other Kir subunits and showed various unique residues at conserved sites, particularly near the pore region. High levels of Kir7.1 transcripts were detected in rat brain, lung, kidney, and testis. In situ hybridization of rat brain sections demonstrated that Kir7.1 mRNA was absent from neurons and glia but strongly expressed in the secretory epithelial cells of the choroid plexus (as confirmed by in situ patch-clamp measurements). In cRNA-injected Xenopus oocytes Kir7.1 generated macroscopic Kir currents that showed a very shallow dependence on external K+ ([K+](e)), which is in marked contrast to all other Kirchannels. At a holding potential of -100 mV, the inward current through Kir7.1 averaged -3.8 +/- 1.04 mu A with 2 mM [K+](e) and -4.82 +/- 1.87 mu A with 96 mM [K+](e). Kir7.1 has a methionine at position 125 in the pore region where other Kir channels have an arginine. When this residue was replaced by the conserved arginine in mutant Kir7.1 channels, the pronounced dependence of K+ permeability on [K+](e), characteristic for other Kir channels, was restored and the Ba2+ sensitivity was increased by a factor of similar to 25 (K-i = 27 mu M). These findings support the important role of this site in the regulation of K+ permeability in Kir channels by extracellular cations.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/09/20 alle ore 09:21:44