Dual activation of a sex pheromone-dependent ion channel from insect olfactory dendrites by protein kinase C activators and cyclic GMP.

Olfactory transduction is thought to take place in the outer dendritic membrane of insect olfactory receptor neurons. Here we show that the outer dendritic plasma membrane of silkmoth olfactory receptor neurons seems to be exclusively equipped with a specific ion channel activated by low concentrations of the species-specific sex pheromone component. This so-called AC1 channel has a conductance of 56 pS and is nonselectively permeable to cations. The AC1 channel can be activated from the intracellular side by protein kinase C activators such as diacylglycerol and phorbolester and by cGMP but not by Ca2+, inositol 1,4,5-triphosphate, or cAMP. Our results imply that phosphorylation of this ion channel by protein kinase C could be the crucial step in channel opening by sex pheromones.