Distinct conformational changes in activated agonist-bound and agonist-free glycine receptor subunits

Pless, Stephan and Lynch, Joseph W. (2009) Distinct conformational changes in activated agonist-bound and agonist-free glycine receptor subunits. Journal Of Neurochemistry, 108 6: 1585-1594. doi:10.1111/j.1471-4159.2009.05930.x


Author Pless, Stephan
Lynch, Joseph W.
Title Distinct conformational changes in activated agonist-bound and agonist-free glycine receptor subunits
Journal name Journal Of Neurochemistry   Check publisher's open access policy
ISSN 0022-3042
1471-4159
Publication date 2009-01-01
Year available 2009
Sub-type Article (original research)
DOI 10.1111/j.1471-4159.2009.05930.x
Open Access Status
Volume 108
Issue 6
Start page 1585
End page 1594
Total pages 10
Editor Murphy, Sean
Turner, Tony J.
Place of publication United Kingdom
Publisher Wiley-Blackwell Publishing Ltd.
Language eng
Subject C1
110903 Central Nervous System
920111 Nervous System and Disorders
Abstract Ligand binding to Cys-loop receptors produces either global conformational changes that lead to activation or local conformational changes that do not. We found that the fluorescence of a fluorophore tethered to R271C in the extracellular M2 region of the alpha 1 glycine receptor increases during glycine activation but not during ivermectin activation. This prompted the hypothesis that this signal reports a glycine-mediated conformational change not essential for activation. We tested this by investigating whether the fluorescence signal depended on whether the fluorophore was attached to a glycine-free or a glycine-bound subunit. Agonist-free subunits were created by incorporating T204A and R65K mutations, which disrupted glycine binding to both (+) and (-) subunit interfaces. In heteromeric receptors comprising wild-type and R65K,T204A,R271C triple-mutant subunits, the fluorescence response exhibited a drastically reduced glycine sensitivity relative to the current response. Two conclusions can be drawn from this. First, because the labeled glycine-free subunits were activated by glycine binding to neighboring wild-type subunits, our results provide evidence for a cooperative activation mechanism. However, because the fluorescent label on glycine-free subunits does not reflect movements at the channel gate, we conclude that glycine binding also produces a local non-concerted conformational change that is not essential for receptor activation.
Keyword Biochemistry & Molecular Biology
Neurosciences
Biochemistry & Molecular Biology
Neurosciences & Neurology
BIOCHEMISTRY & MOLECULAR BIOLOGY
NEUROSCIENCES
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
Queensland Brain Institute Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 11 times in Scopus Article | Citations
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Created: Tue, 19 May 2009, 22:49:28 EST by Debra McMurtrie on behalf of Queensland Brain Institute