RIC-3 enhances functional expression of multiple nicotinic acetylcholine receptor subtypes in mammalian cells.

Recent studies have shown that RIC-3, originally identified in Caenorhabditis elegans as the protein encoded by the gene resistance to inhibitors of cholinesterase (ric-3), can enhance functional expression of alpha7 nicotinic acetylcholine receptors (nAChRs). In the present study, the influence of C. elegans and human RIC-3 upon multiple homomeric (alpha7, alpha8, and alpha9) and heteromeric (alpha3beta2, alpha3beta4, alpha4beta2, alpha4beta4, and alpha9alpha10) nAChR subtypes has been examined in transfected mammalian cells by radioligand binding and functional characterization.

Pharmacological properties of alpha 9 alpha 10 nicotinic acetylcholine receptors revealed by heterologous expression of subunit chimeras.

The nicotinic acetylcholine receptor (nAChR) alpha9 and alpha10 subunits are expressed primarily within hair cells of the inner ear and have been implicated in auditory processing. Although functional recombinant nAChRs generated by the coexpression of alpha9 and alpha10 in Xenopus laevis oocytes have been described previously, there have been no reports of the successful heterologous expression of alpha9alpha10 nAChRs in cultured cell lines. In this study, subunit chimeras (alpha9chi and alpha10chi) have been constructed that contain the extracellular, ligand binding domain of the alpha9 or alpha10 subunits fused to the C-terminal domain of the 5-hydroxytryptamine type 3A (5HT3A) subunit.