Insect odorant receptor (OR (sometimes written as OrX for variable subunits and Orco for the conserved co-receptor))

Insect odorant receptors are unique ligand-gated ion channels found in insect olfactory sensory neurons, responsible for detecting airborne chemical cues like odors and pheromones.[2][5][9] Each functional receptor is a heteromeric complex comprising a variable, odorant-selective subunit (OrX) and a highly conserved co-receptor (Orco).[4][5] Upon binding an odorant molecule, the OrX subunit undergoes conformational change, opening a central channel pore to allow cation influx and neural activation.[1][2][7] While insect odorant receptors structurally resemble seven-transmembrane proteins, they are unrelated to vertebrate GPCRs and their seven-helix architecture is distinct in topology and function.[3][5] Insects rely on these receptors for critical behaviors like foraging, mating, and species recognition, making them important targets for insect control strategies and the development of novel repellents or attractants.[7][9]

Other names

Insect OROlfactory receptor (in insects)Odorant receptor (insects)Orco (Odorant receptor co-receptor, the conserved subunit)Tuning OR (OrX, the variable odorant-selective subunit)

Direct agonism of the ligand-binding subunit (odorant/repellent binds and activates); Allosteric modulation (via Orco co-receptor or synthetic ligands like VUAA1); Channel opening allows non-selective cation influx, leading to neuronal depolarization and signal initiation