G-protein activation, identification and immunolocalization in pheromone-sensitive sensilla trichodea of moths

Abstract

Electrophysiological in situ recordings from pheromone-sensitive sensilla trichodea of Bombyx mori males with a recording pipette which contained G-protein-activating fluoride, showed receptor cell activity similar to that evoked by pheromone stimulation. This suggests that G-proteins might be physiologically active in olfactory sensilla of insects in situ. Biochemical experiments using specific antibodies revealed the presence of G-protein, belonging to the Gq family, in antennal preparations. Similar G-protein was identified in sensory hair preparations of Antheraea pernyi which contained only cuticle, sensillum lymph and dendritic material. Moreover, the absence of this G-protein in pure sensillum lymph preparations indicates its association with the receptive dendrites. This particular association could be shown by immunolabelling studies at the ultrastructural level. Strong specific labelling of membranes of receptor-cell dendrites was found in all types of olfactory sensilla present on the antenna of the silkmoths. Additional specific labelling of apical membranes of auxiliary cells, epidermal cells and membranes forming the axon/glia interface demonstrated that this G-protein is not restricted to the sensory dendrites and that other signal-transduction pathways could be present at these membranes. In summary, the experiments imply a participation of G-protein of the Gq family in signal transduction of olfactory receptor cells in moths.

Intracellular regulation of the insect chemoreceptor complex impacts odor localization in flying insects

“…Obviously, a similar role for intracellular signalling in ORs of other pterygote orders must be demonstrated to give credence to this hypothesis. However, the aforementioned homology of Orco across several insect orders, and the expression of similar intracellular signalling proteins in the dendrite of other insects (Laue et al, 1997;Miura et al, 2005;Maida et al, 2000), suggests that such signalling may be common across the Pterygota.…”

Molecular genetics and evolution of pheromone biosynthesis in Lepidoptera

“…As we have already shown, all of these occur in the insect desaturase multigene family. In addition, we believe that the male moth pheromone-receptor system, which is composed of olfactory receptor loci (47,48), may also be subject to a birth-and-death model of evolution, perhaps as a result of coevolution with the desaturase multigene family. A large and diverse olfactory receptor multigene family would provide an adaptive advantage for male moths, allowing for the rapid evolution of male response to female pheromone blends (Fig.…”

Cloning of the 16-kDa V-ATPase proteolipid subunit from the red imported fire antSolenopsis invicta buren (Hymenoptera: Formicidae)

“…A potassium/proton antiport is thought to drive the receptor current in antennal neurons when ion channels in the dendritic membrane are opened (Klein and Zimmerman, 1991). Electrophysiological and immunological evidence indicates that Gproteins mediate the response of receptor cells in the sensilla trichodea of moth antennae to pheromone stimulation (Laue et al, 1997). Although olfaction is not well understood in insects, based on this evidence it would seem that G-protein coupled receptors bind odorant molecules, then induce the opening of ion channels in the dendritic membrane, which initiates the antennal receptor current from the voltage generated by the V-ATPase energized epithelium (Klein and Zimmerman, 1991).…”