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Updated: May 7, 2026
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Published on: June 2, 2023
Intermediate closed state for glycine receptor function revealed by cysteine cross-linking
Marie S Prevost1, Gustavo Moraga-Cid, Catherine Van Renterghem
1Channel Receptors Unit, Institut Pasteur, 75015 Paris, France.
Summary
Cysteine cross-linking of the human glycine receptor stabilizes a unique closed state, revealing insights into pentameric ligand-gated ion channel gating mechanisms and conformational changes.
Area of Science:
- Neuroscience
- Structural Biology
- Biochemistry
Background:
- Pentameric ligand-gated ion channels (pLGICs) are crucial for neurotransmission.
- Understanding pLGIC conformational states is key to their function.
- Previous studies stabilized a closed state in prokaryotic GLIC using cysteine cross-linking.
Purpose of the Study:
- To investigate the effect of homologous cysteine cross-linking on the human α1 glycine receptor.
- To characterize the conformational states and gating mechanisms of pLGICs.
Main Methods:
- Electrophysiology was used to study the functional effects of cysteine cross-linking.
- Allosteric modeling was applied to interpret the observed gating phenotypes.
- Structural insights were inferred from functional data.
Main Results:
- Cysteine cross-linking induced a gain-of-function phenotype: constitutive openings, increased agonist potency, and equalized efficacies.
- Maximal currents were reduced, but unitary conductance remained unchanged, an effect reversed by propofol.
- The cross-linking favored a distinct closed state, potentially a gating intermediate or fast-desensitized state.
Conclusions:
- Cysteine cross-linking of the human glycine receptor stabilizes a novel closed conformation.
- This study elucidates the role of extracellular-transmembrane loop movements in orthosteric agonist-mediated gating.
- The findings provide structural and functional insights into pLGIC gating dynamics.
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