The Insulin Signaling Pathway and Aging in Drosophila

In the nematode worm C. elegans, mutation of genes encoding components of the insulin/Insulinlike Growth Factor (IGF) signaling pathway extends the lifespan of the adult worm. They also confer resistance to environmental stresses such as heat and oxidation, and are associated with increased levels of antioxidant defenses. These mutations were discovered because they also control entry to an alternative route of development, to a growth-arrested, non-feeding, fat-storing, stress-resistant dauer larva that is produced in response to crowding. Thus, the extension of adult lifespan by these mutations could be a peculiarity of C. elegans, resulting from the pathway’s function in the regulation of the dauer developmental route.