The antennae of the fruit fly Drosophila melanogaster are shown schematically in dark yellow. Dark red: odor molecules. Right: The odorant receptors studied are protein dimers consisting of the odorant receptor Or22a and the co-receptor Orco; they mediate very sensitive responses to odor molecules. Above: State of sensitization -- weak ion flow caused by cAMP; below: signals are "switched through" in the receptor system resulting in opening of the ion channel and electric signal transduction. The pictures are taken from the animation.
Graphics: Dieter Wicher, Max Planck Institute for Chemical Ecology. Animation: Moves Like Nature, Kimberly Falk, Jena