Researchers at UT Southwestern Medical Center have discovered how a protein, called an olfactory binding protein, links incoming pheromone signals and specific nerve cells in an insect's brain, which in turn translate those signals. Pheromones are chemical signals given off by animals that, when detected by others of the same species, mediate a variety of behaviors, such as feeding, mating and colonizing.
The findings not only shed light on insect behavior, but also suggest that olfactory binding proteins may be new targets for synthetic chemicals that could trick insects like mosquitoes into traps or could function as repellents, said Dr. Dean Smith, associate professor of pharmacology at UT Southwestern and senior author on the study. Humans give off signals that attract mosquitoes, the insect responsible for spreading malaria, which kills up to 3 million people each year.
The research, appearing in the Jan. 20 issue of the journal Neuron, is the first to directly link pheromone-induced behavior with the activity of olfactory binding proteins, or OBPs.
The nerve cells, or neurons, in insects responsible for picking up on pheromone signals have been studied for decades, as have pheromones themselves. But the biochemical mechanism by which pheromones and other odorants selectively activate those sensory neurons is poorly understood.
"We've known about OBPs for 20 years, but until now their function and significance was unclear," said Dr. Smith, who works in the Center for Basic Neuroscience. Olfactory binding proteins are produced by non-neuronal cells and are secreted into the fluid bathing the dendrites, or nerve endings, of olfactory neurons.