Insect nicotinic acetylcholine receptors (nAChR) are molecular targets of highly effective insecticides. The use of chaperone proteins has been key to successful functional expression of these receptors in heterologous systems, permitting functional and pharmacological studies of insect nAChRs with particular subunit composition. Here, we report the first use of the chaperone protein, NACHO, to enable functional expression of an insect nAChR, the a6 subunit from Apis mellifera, in Xenopus laevis oocytes. This is also the first report of functional expression of a homomeric insect a6 nAChR. Using two-electrode voltage-clamp electrophysiology we show that the acetylcholine EC50 of the a6 receptor is 0.88 microM and that acetylcholine responses are antagonized by a-bungarotoxin. Spinosad showed agonist actions and kept the ion channel open when co-applied with acetylcholine, reinforcing the a6 nAChR subunit as a key molecular target for the spinosyn class of insecticide. The use of NACHO may provide a basis for future expression studies of insect a6 nAChRs, potentially providing a tool for the discovery of novel insecticides.
Hawkins, JosephMitchell, Eleanor L. Jones, Andrew K.
Department of Biological and Medical Sciences
Year of publication: 2021Date of RADAR deposit: 2022-01-06