NACHO permits functional heterologous expression of an insect homomeric α6 nicotinic acetylcholine receptor

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 alpha 6 subunit from Apis mellifera, in Xenopus ktevis oocytes. This is also the first report of functional expression of a homomeric insect alpha 6 nAChR. Using two-electrode voltage-clamp electrophysiology we show that the acetylcholine EC50 of the alpha 6 receptor is 0.88 mu M and that acetylcholine responses are antagonized by alpha-bungarotoxin. Spinosad showed agonist actions and kept the ion channel open when co-applied with acetylcholine, reinforcing the alpha 6 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 alpha 6 nAChRs, potentially providing a tool for the discovery of novel insecticides.

Automated summary

This study successfully achieved the functional expression of insect α6 subunit in heterologous systems using the chaperone protein NACHO for the first time. It also reported the functional expression of homomeric insect α6 nAChR for the first time. The results showed that the acetylcholine EC50 of the α6 receptor was 0.88 μM, and acetylcholine responses were antagonized by α-bungarotoxin. Furthermore, spinosad exhibited agonist actions and kept the ion channel open when co-applied with acetylcholine, confirming α6 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 α6 nAChRs, potentially providing a tool for the discovery of novel insecticides.