Murray, Teresa A. and Bertrand, Daniel and Papke, Roger L. and George, Andrew A. and Pantoja, Rigo and Srinivasan, Rahul and Liu, Qiang and Wu, Jie and Whiteaker, Paul and Lester, Henry A. and Lukas, Ronald J. (2012) α7β2 Nicotinic Acetylcholine Receptors Assemble, Function, and Are Activated Primarily via Their α7-α7 Interfaces. Molecular Pharmacology, 81 (2). pp. 175-188. ISSN 0026-895X http://resolver.caltech.edu/CaltechAUTHORS:20120214-145000544
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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 laevis 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 nAChRs composed of wild-type subunits or fluorescently tagged subunits had pharmacological properties similar to those of α7 nAChRs, although amplitudes of α7β2 nAChR-mediated, agonist-evoked currents were generally ∼2-fold lower than those for α7 nAChRs. It is noteworthy that α7β2 nAChRs displayed sensitivity to low concentrations of the antagonist dihydro-β-erythroidine that was not observed for α7 nAChRs 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 nAChRs. On the basis of our findings, we have constructed a model predicting receptor function that is based on stoichiometry and position of β2 subunits within the α7β2 nAChRs.
|Additional Information:||© 2012 The American Society for Pharmacology and Experimental Therapeutics. Received June 12, 2011; accepted October 28, 2011. This work was supported by the National Institutes of Health National Institute on Drug Abuse [Grants DA015389, DA027070, DA012242]; the National Institutes of Health National Institute of Neurological Diseases and Stroke [Grant NS11756]; the National Institutes of Health National Institute of Mental Health [Grant MH086383]; the National Institutes of Health National Institute of General Medical Sciences [Grant GM057481]; a US National Science Foundation Graduate Research Fellowship; the Barrow Neurological Foundation; a Catholic Healthcare West SEED Grant; the Biodesign Institute at Arizona State University, the Swiss National Science Foundation; the EC Neurocypres Grant; and the California Tobacco-Related Disease Research Program. Authorship Contributions: Participated in research design: Murray, Bertrand, Papke, George, Pantoja, Srinivasan, Liu, Wu, Whiteaker, Lester, and Lukas. Conducted experiments: Murray, Bertrand, Papke, George, and Liu. Performed data analysis: Murray, Bertrand, Papke, George, and Liu. Wrote or contributed to the writing of the manuscript: Murray, Bertrand, Papke, George, Liu, Whiteaker, Lester and Lukas.|
|Official Citation:||Teresa A. Murray, Daniel Bertrand, Roger L. Papke, Andrew A. George, Rigo Pantoja, Rahul Srinivasan, Qiang Liu, Jie Wu, Paul Whiteaker, Henry A. Lester, and Ronald J. Lukas α7β2 Nicotinic Acetylcholine Receptors Assemble, Function, and Are Activated Primarily via Their α7-α7 Interfaces Mol Pharmacol February 2012 81:175-188; published ahead of print October 28, 2011, doi:10.1124/mol.111.074088|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||14 Feb 2012 23:20|
|Last Modified:||14 Feb 2012 23:20|
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