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| Research article summary (published 30 Dec 2001): |
Control of kinetic properties of GluR2 flop AMPA-type channels: impact of R/G nuclear editing.
Full Abstract
The GluR2 flop subunit of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors greatly determines calcium permeability and kinetic properties of heteromeric AMPA subunit assemblies. Post-transcriptional editing of this subunit at the Q/R/N site controls calcium permeability whereas editing at the R/G site is involved in the regulation of biophysical properties. We used patch-clamp techniques with ultrafast solution exchange to examine the kinetics of recombinant human homomeric GluR2 flop channels transiently expressed in HEK293 cells [edited at the R/G site and Q/R/N site (GR), and unedited (RN) and edited (GN) at the R/G site both with asparagine (N) at the Q/R/N site]. The time constant of desensitization after application of 10 mm glutamate was 1.38 +/- 0.05 ms (n = 10), 5.53 +/- 0.57 ms (n = 7) and 1.33 +/- 0.06 ms (n = 12) for the GluR2 flop GR, RN and GN channels, respectively. The time constant of resensitization was 75 ms for the GluR2 flop RN and 30 ms for the GN channels. The dose-dependence of the peak current amplitude, kinetics of activation and deactivation, and peak open probability did not differ between RN and GN channels. The study shows that desensitization and resensitization kinetics of homomeric GluR2 flop channels are controlled by a single amino acid exchange (glycine by arginine) at the R/G site. Quantitative analysis by computer simulation using a circular kinetic scheme allows the prediction of the main experimental results.
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Author information
Author/s: Krampfl, Klaus (K); Schlesinger, Friedrich (F); Zörner, Antje (A); Kappler, Martin (M); Dengler, Reinhard (R); Bufler, Johannes (J);
Affiliation: Department of Neurology, Medizinische Hochschule Hannover, 31623 Hannover, Germany.
Journal and publication information
Publication Type: Journal Article; Research Support, Non-U.S. Gov't
Journal: The European journal of neuroscience (Eur J Neurosci), published in France. (Language: eng)
Reference: 2002-Jan; vol 15 (issue 1) : pp 51-62
Dates: Created 2002/02/25; Completed 2002/04/25; Revised 2006/11/15;
PMID: 11860506, status: MEDLINE (last retrieval date: 11/6/2008)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
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