Odorant receptor co-receptor (Orco)

Odorant receptor co-receptor (Orco) is a highly conserved, obligate subunit required for functional olfactory signaling in insects. Unlike conventional odorant receptors that determine odor specificity, Orco interacts with these receptors to form heteromeric, ligand-gated ion channels that transduce chemosensory signals upon odorant binding. Orco does not directly bind odorants but is essential for the correct cellular trafficking, membrane localization, and functional activity of the receptor complexes[3][4][6]. Structural studies, including cryo-EM, show that Orco forms tetrameric channels permeable to cations such as Ca²⁺, and can be directly activated by synthetic agonists like VUAA1[4][6]. Orco’s unique structure and function, distinct from mammalian olfactory GPCRs, make it an attractive target for controlling insect behavior, deterring disease vectors, and developing novel insect repellents with greater specificity and efficacy than current agents[4][5][6].

Other names

OrcoORcoOlfactory receptor co-receptorOdorant receptor 83b (Drosophila: Or83b)Coreceptor of odorant receptor

Agonists (e.g., VUAA1) directly activate Orco ion channels, bypassing conventional odorant binding Antagonists (repellents) may inhibit Orco function, reducing olfactory signaling and altering insect behavior