Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Tryptophan substitutions at lipid-exposed positions of the gamma M3 transmembrane domain increase the macroscopic ionic current response of the Torpedo californica nicotinic acetylcholine receptor
Autore:
Cruz-Martin, A; Mercado, JL; Rojas, LV; McNamee, MG; Lasalde-Dominicci, JA;
Indirizzi:
Univ Puerto Rico, Dept Biol, San Juan, PR 00931 USA Univ Puerto Rico San Juan PR USA 00931 Dept Biol, San Juan, PR 00931 USA Univ Cent Caribe, Sch Med, Dept Physiol, Bayamon, PR 00960 USA Univ Cent Caribe Bayamon PR USA 00960 Dept Physiol, Bayamon, PR 00960 USA Univ Calif Davis, Sect Mol & Cellular Biol, Livermore, CA 95616 USA Univ Calif Davis Livermore CA USA 95616 lar Biol, Livermore, CA 95616 USA
Titolo Testata:
JOURNAL OF MEMBRANE BIOLOGY
fascicolo: 1, volume: 183, anno: 2001,
pagine: 61 - 70
SICI:
0022-2631(20010901)183:1<61:TSALPO>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
NONCOMPETITIVE ANTAGONIST; CHANNEL FUNCTION; DELTA-SUBUNIT; ALPHA-SUBUNIT; BINDING-SITE; AMINO-ACIDS; M4 DOMAIN; MUTATIONS; SEGMENT; RESOLUTION;
Keywords:
acetylcholine receptor; M3 transmembrane segment; macroscopic response; voltage-clamp;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Lasalde-Dominicci, JA Univ Puerto Rico, Dept Biol, POB 23360, San Juan, PR00931 USA Univ Puerto Rico POB 23360 San Juan PR USA 00931 USA
Citazione:
A. Cruz-Martin et al., "Tryptophan substitutions at lipid-exposed positions of the gamma M3 transmembrane domain increase the macroscopic ionic current response of the Torpedo californica nicotinic acetylcholine receptor", J MEMBR BIO, 183(1), 2001, pp. 61-70

Abstract

Our previous amino-acid substitutions at the postulated lipid-exposed transmembrane segment M4 of the Torpedo californica acetylcholine receptor (AChR) focused on the alpha subunit. In this study we have extended the mutagenesis analysis using single tryptophan replacements in seven positions (I288, M291 F292, S294. L296, M299 and N300) near the center of the third transmembrane domain of the gamma subunit (gamma M3). All the tryptophan substitution mutants were expressed in Xenopus laevis oocytes following mRNA injections at levels close to wild type. The functional response of these mutantswas evaluated using macroscopic current analysis in voltage-clamped oocytes. For all the substitutions the concentration for half-maximal activation,EC50 is similar to wild type using acetylcholine. For F292W, L296W and M299W the normalized macroscopic responses are 2- to 3-fold higher than for wild type. Previous photolabeling studies demonstrated that these three positions were in contact with membrane lipids. Each of these M3 mutations was co-injected with the previously characterized alpha C418W mutant to examine possible synergistic effects of single lipid-exposed mutations on two different subunits. For the gamma M3/alpha M4 double mutants, the EC(50)s were similar to those measured for the alpha C418W mutant alone. Tryptophan substitutions at positions that presumably face the interior of the protein (S294 and M291) or neighboring helices (I288) did not cause significant inhibition of channel function or surface expression of AChRs.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 04:44:52