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Insect olfactory transduction is a fast developing research field. Up to now most investigations have focussed on the characteristics of olfactory receptors and on their activation, while signal response termination, which is critical to understand the adaptive properties of olfaction in insects, has received scant attention.
There is growing evidence about a dual nature of the cationic depolarizing current that can be recorded following olfactory activation. Odor stimulation produces a rapid and transient ionotropic current, which is followed by a delayed and slow metabotropic one induced by an increase in the intracellular concentration of cAMP, which binds to Orco co-receptor increasing its sensitivity. In both cases the opening of the ion pores raises the intracellular Ca2+ concentration, and leads to the neuron depolarization.
Calmodulin is a central hub in the cellular Ca2+ homeostasis, regulating many signaling pathways following its elevation including their stop, and the Ca2+ clearance, but its importance in shaping the properties of olfactory response in insects is completely unexplored.

My project aims to investigate the role of Calmodulin in shaping the odor response termination in Drosophila melanogaster, using several techniques to study it from the cellular to the behavioural level. In particular, using Calmodulin-mutated fly strains I want to explore the importance of different Calmodulin Ca2+-binding sites in shaping the intracellular Ca2+ and cAMP dynamics, which influence signal transduction and receptor sensitivity respectively. Moreover, using behavioural assays I want to investigate the behavioural consequences of Calmodulin activity disruption on e.g. odor sensitivity and odor discrimination. Finally, using Mass Spectrometry-based techniques, I will investigate the folding and the topology of Orco co-receptor, which are still unexplored but essential in order to understand the mechanism of olfactory transduction.
last updated on 2013-04-10