Mosquitoes use three main receptor types—Odorant Receptors (ORs), Ionotropic Receptors (IRs), and Gustatory Receptors (GRs)—located on their antennae and palps to detect hosts, particularly sensing CO2, skin odors, and body heat. ORs form complexes with the Orco co-receptor, detecting general odors, while GRs are key for CO2, and IRs respond to various molecules, all converting chemical signals to electrical impulses for host-seeking.
Key Receptor Types
- Odorant Receptors (ORs): G protein-coupled receptors (GPCRs) that detect a wide range of volatile compounds, working with the conserved Orco subunit.
- Ionotropic Receptors (IRs): Detect diverse molecules, playing a role in sensing human cues.
- Gustatory Receptors (GRs): Crucial for detecting carbon dioxide (CO2), a primary host attractant, often forming complexes with specific subunits (e.g., Gr1, Gr2, Gr3).
How They Work
- Detection: Mosquitoes have tiny sensory hairs (sensilla) on their antennae, palps, and proboscis containing these receptors.
- Binding: Odor-binding proteins (OBPs) carry attractants (like CO2, lactic acid, sweat components) to the receptors.
- Signal Transduction: Receptors act as ion channels, opening when a molecule binds, creating an electrical signal.
- Brain Processing: Neurons carry these signals to the mosquito’s brain, guiding it toward a host.
Targets for Control
- Repellents: Many repellents work by interfering with these receptors, blocking or masking signals.
- Viral Receptors: Mosquitoes also have cell surface receptors (like LDLR family, MXRA8) that viruses use to infect them, which are targets for antiviral research. (Kris Cahyo Mulyatno)
