Sensory sea slugs: Towards decoding the molecular toolkit required for a mollusc to smell

Molluscs are a large and diverse group of aquatic and terrestrial animals that rely heavily on chemical communication. Aplysia is an excellent model in which to investigate and develop breakthrough principles into the molecular aspects of chemoreception in molluscs. We recently identified a large family of rhodopsin-like G-protein coupled receptors expressed in the chemosensory rhinophore of Aplysia that may be key components of sensory detection. Here, we summarize these findings and provide further insight into the molecular olfactory toolkit used by Aplysia, by taking advantage of our knowledge of their attraction pheromones. Our characterization of rhinophore genes upregulated following pheromone stimulation helps explain the dynamics of olfactory gene expression following chemical stimulation.