Functional characterization of neurotransmitter activation and modulation in a nematode model ligand‐gated ion channel

• DOI: 10.1111/jnc.13644
• Publication Date: 2016-04-22T21:08:45Z
• Authors: Stephanie A. Heusser; Özge Yoluk; Göran Klement; Erika A. Riederer; Erik Lindahl; Rebecca J. Howard
• Keywords: Chloride channel; Neurotransmitter receptor

The superfamily of pentameric ligand-gated ion channels includes neurotransmitter receptors that mediate fast synaptic transmission in vertebrates, and are targets for drugs including alcohols, anesthetics, benzodiazepines, anticonvulsants. However, the mechanisms channel opening, gating, modulation these leave many open questions, despite their pharmacological importance. Subtle conformational changes both extracellular transmembrane domains likely to influence but have been difficult characterize given limited structural data available human membrane proteins. Recent crystal structures a modified Caenorhabditis elegans glutamate-gated chloride (GluCl) multiple states offer an appealing model system structure-function studies. pharmacology crystallographic GluCl construct is not well established. To establish functional relevance this system, we used two-electrode voltage-clamp electrophysiology Xenopus oocytes activation native-like constructs by L-glutamate ivermectin. We also tested ethanol other anesthetic agents, site-directed mutagenesis explore role region Loop F which was implicated ligand gating molecular dynamics simulations. Our findings indicate functionally models concentration-dependent agonism allosteric pharmacologically relevant receptors. Specific substitutions at residue Leu174 loop altered direct activation, consistent with computational evidence region's binding. These insights demonstrate conservation properties receptor family, framework as new possibilities drug discovery. In study, elucidate validity (GluClcryst ) structurally accessible GABAA contrast controls, GluClcryst exhibits classical its L-glutamate. sensitive modulators associated receptors, mutations predicted alter opening.