Drosophila serves as a suitable in vivo system to model AD-associated protein function, as the fruit fly contains functional homologs of all the necessary components of the γ-secretase complex (Guo et al., 2003; Ganguly et al., 2008; Chakraborty et al., 2011), and can process expressed human APP (Fossgreen et al., 1998), displaying adult phenotypes that are easily identifiable and have broad phenotypic ranges for genetic studies. This evidence concerns the gene APP and Alzheimer disease.