RT Journal Article
SR Electronic
T1 α7β2 nAChRs Assemble and Function, and are Activated Primarily Via their α7-α7 Interfaces
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.111.074088
DO 10.1124/mol.111.074088
A1 Teresa Ann Murray
A1 Daniel Bertrand
A1 Roger L Papke
A1 Andrew A George
A1 Rigo Pantoja
A1 Rahul Srinivasan
A1 Qiang Liu
A1 Jie Wu
A1 Paul Whiteaker
A1 Henry A Lester
A1 Ronald J Lukas
YR 2011
UL http://molpharm.aspetjournals.org/content/early/2011/10/28/mol.111.074088.abstract
AB We investigated assembly and function of nicotinic acetylcholine receptors (nAChRs) composed of α7 and β2 subunits. We measured optical and electrophysiological properties of wild type and mutant subunits expressed in cell lines and Xenopus oocytes. Laser scanning confocal microscopy indicated that fluorescently tagged α7 and β2 subunits colocalize. Förster resonance energy transfer between fluorescently tagged subunits strongly suggested that α7 and β2 subunits coassemble. Total internal reflection fluorescence microscopy revealed that assemblies localized to filopodia-like processes of SH-EP1 cells. Gain-of-function α7 and β2 subunits confirmed that these subunits coassemble within functional receptors. Moreover, α7β2 nAChR composed of wild type subunits or fluorescently tagged subunits had similar pharmacological properties to α7 nAChR, although amplitudes of α7β2 nAChR-mediated, agonist-evoked currents generally were ~2-fold lower than those for α7 nAChR. Notably, α7β2 nAChR displayed sensitivity to low concentrations of the agonist dihydro-β-erythroidine that was not observed for α7 nAChR at comparable concentrations. In addition, cysteine mutants revealed that the α7-β2 subunit interface does not bind ligand in a functionally-productive manner, partly explaining lower α7β2 nAChR current amplitudes and challenges in identifying the function of native α7β2 nAChR. Based on our findings, we have constructed a model predicting receptor function based on stoichiometry and position of β2 subunits within the α7β2 nAChR.