Ethanol Modulation is Quantitatively Determined by the Transmembrane Domain of Human α 1 Glycine Receptors

Autor: Suzzane Horani, James R. Trudell, Evan P. Stater, R. Adron Harris, Rebecca J. Howard, P.J. Corringer
Přispěvatelé: University of Texas at Austin [Austin], Skidmore College [Saratoga Springs], Récepteurs Canaux - Channel Receptors, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Stanford School of Medicine [Stanford], Stanford Medicine, Stanford University-Stanford University, This work was supported by the National Institutes of Health National Institute on Alcohol Abuse and Alcoholism (R01 AA06399 to RAH, R01 AA013378 to JRT, and F32 AA019875‐01 to RJH) and by the Skidmore College Summer Faculty/Student Research Program., Thanks to C.M. Borghese and G. Duret for helpful technical and conceptual discussions and to Jody Mayfield for valuable editorial assistance, Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur [Paris]
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Alcoholism: Clinical and Experimental Research
Alcoholism: Clinical and Experimental Research, 2015, 39 (6), pp.962-968. ⟨10.1111/acer.12735⟩
Alcoholism: Clinical and Experimental Research, Wiley, 2015, 39 (6), pp.962-968. ⟨10.1111/acer.12735⟩
ISSN: 0145-6008
1530-0277
Popis: BACKGROUND Mutagenesis and labeling studies have identified amino acids from the human α1 glycine receptor (GlyR) extracellular, transmembrane (TM), and intracellular domains in mediating ethanol (EtOH) potentiation. However, limited high-resolution structural data for physiologically relevant receptors in this Cys-loop receptor superfamily have made pinpointing the critical amino acids difficult. Homologous ion channels from lower organisms provide conserved models for structural and functional properties of Cys-loop receptors. We previously demonstrated that a single amino acid variant of the Gloeobacter violaceus ligand-gated ion channel (GLIC) produced EtOH and anesthetic sensitivity similar to that of GlyRs and provided crystallographic evidence for EtOH binding to GLIC. METHODS We directly compared EtOH modulation of the α1 GlyR and GLIC to a chimera containing the TM domain from human α1 GlyRs and the ligand-binding domain of GLIC using 2-electrode voltage-clamp electrophysiology of receptors expressed in Xenopus laevis oocytes. RESULTS EtOH potentiated α1 GlyRs in a concentration-dependent manner in the presence of zinc-chelating agents, but did not potentiate GLIC at pharmacologically relevant concentrations. The GLIC/GlyR chimera recapitulated the EtOH potentiation of GlyRs, without apparent sensitivity to zinc chelation. For chimera expression in oocytes, it was essential to suppress leakage current by adding 50 μM picrotoxin to the media, a technique that may have applications in expression of other ion channels. CONCLUSIONS Our results are consistent with a TM mechanism of EtOH modulation in Cys-loop receptors. This work highlights the relevance of bacterial homologs as valuable model systems for studying ion channel function of human receptors and demonstrates the modularity of these channels across species.
Databáze: OpenAIRE
Externí odkaz: