We previously have shown that Î²3 subunits either eliminate (e.g. for all-human (h) or all-mouse (m)Î±6Î²4Î²3-nAChR) or potentiate (e.g. for hybrid mÎ±6hÎ²4hÎ²3- or mÎ±6mÎ²4hÎ²3- nAChR containing subunits from different species) function of Î±6*-nAChR expressed in Xenopus oocytes, and that nAChR hÎ±6 subunit residues Asn-143 and Met-145 in N-terminal domain loop E are important for dominant-negative effects of nAChR hÎ²3 subunits on hÎ±6*-nAChR function. Here, we tested the hypothesis that these effects of Î²3 subunits would be preserved even if nAChR Î±6 subunits harbored gain-of-function, leucine- or valine-to-serine mutations at 9â€² or 13â€² positions (L9â€²S or V13â€²S) in their second transmembrane domains, yielding receptors with heightened functional activity and more amenable to assessment of effects of Î²3 subunit incorporation. However, coexpression with Î²3 subunits potentiates rather than suppresses function of all-human, all-mouse, or hybrid Î±6 (L9â€²S or V13â€²S)Î²4*- or Î±6(N143D+M145V) L9â€²SÎ²2*-nAChR. This contrasts with the lack of consistent function when Î±6 (L9â€²S or V13â€²S) and Î²2 subunits are expressed alone or in the presence of wild-type Î²3 subunits. These results provide evidence that gain-of-function hÎ±6hÎ²2*-nAChR (i.e. hÎ± 6(N143D+M145V) L9â€²ShÎ²2hÎ²3 nAChR) could be produced in vitro. These studies also indicate that nAChR Î²3 subunits can be assembly partners in functional Î±6*-nAChR and that 9â€² or 13â€² mutations in the nAChR Î±6 subunit second transmembrane domain can act as gain-of-function and/or reporter mutations. Moreover, our findings suggest that Î²3 subunit coexpression promotes function of Î±6*-nAChR. Â© 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
Journal of Biological Chemistry
Digital Object Identifier (DOI)
Dash, Bhagirathi and Lukas, Ronald J., "Modulation Of Gain-Of-Function Î±6*-Nicotinic Acetylcholine Receptor By Î²3 Subunits" (2012). Neurobiology. 249.