Insect olfactory receptor (OR)

Insect olfactory receptors (ORs) are specialized chemosensory proteins located on the dendrites of olfactory sensory neurons within insect antennae and maxillary palps. Unlike vertebrate odorant receptors, which are G protein-coupled receptors, insect ORs possess an inverted membrane topology and function as heteromeric, ligand-gated ion channels composed of a unique odorant-binding subunit and a ubiquitous co-receptor called Orco (Wicher et al., 2008, Nature). These receptors are essential for mediating critical survival behaviors, including the location of food sources, mating partners, and suitable hosts for blood-feeding insects. Because many insects serve as vectors for global infectious diseases like malaria and Zika virus, ORs are primary targets for the development of chemical repellents and attractants (Vosshall & Hansson, 2011, Chemical Senses). By pharmacologically targeting the OR/Orco complex, researchers can disrupt the sensory perception of insects, effectively masking human hosts or creating 'confusion' that prevents disease transmission. The structural uniqueness of these receptors compared to human proteins makes them attractive targets for selective pest control with minimized human toxicity.

Other names

Odorant receptorInsect OROrco complexInsect chemosensory receptor7-transmembrane odorant receptor

Insect olfactory receptors function as heteromeric complexes consisting of a variable odorant-binding subunit (OR) and a highly conserved co-receptor (Orco). These complexes act as ligand-gated non-selective cation channels (Sato et al., 2008, Nature). Repellents like DEET can act as competitive inhibitors or allosteric modulators that disrupt the binding of natural odorants or alter the channel's gating properties, thereby interfering with the insect's ability to detect host-derived chemical cues (Leal, 2013, Annual Review of Entomology). Some synthetic compounds, such as VUAA1, act as direct agonists of the Orco subunit, leading to overstimulation and exhaustion of the olfactory sensory neurons (Jones et al., 2011, PNAS).