In this week’s Cell, a completely new idea about how pheromones work at the molecular level is described for fruit flies.
Activation of Pheromone-Sensitive Neurons Is Mediated by Conformational Activation of Pheromone-Binding Protein. John D. Laughlin, Tal Soo Ha, David N.M. Jones and Dean P. Smith. Cell 133(7). doi:10.1016/j.cell.2008.04.046
You might remember that pheromones are detected by insects’ antennae–it’s been assumed that the pheromone molecule attached to a protein on the nerve cell surface, initiating a depolarization reaction, and ultimately changing the animal’s behavior by stimulating the nervous system.
In this study, they discovered that in fruit flies (Drosophila melanogaster), pheromone actually attaches to a free-floating protein with the catchy name of LUSH. Remember, proteins aren’t just straight chains of amino acids. Larger proteins have a tertiary structure (illustrated nicely here for non-science types with a telephone cord). By binding to the molecule, the pheromone changes the shape of LUSH.
It’s the new, altered LUSH that actually binds and activates the neuron, not the pheromone molecule!
This is important not just because it’s a cool bit of science that shows us the inner workings of an antenna, but because it gives us an additional potential target to attack for pest insects.
One tweak the authors of this paper did was to genetically alter some of the amino acids in LUSH to change the shape of the molecule. They produced an altered LUSH molecule that could produce a neural reaction–even though there was no pheromone present!
IF this mechanism is active in other insects, and IF we can find a way to bind up LUSH or alter it, we could completely prevent an insect from ever detecting its species’ pheromones. No pheromone detection = disruption of mating, which would be a pretty nifty form of bug birth control.