Bader, R., Sarraf-Zadeh, L., Peters, M., Moderau, N., Stocker, H., Köhler, K., Pankratz, M.J., Hafen, E. (2013). The IGFBP7 homolog Imp-L2 promotes insulin signaling in distinct neurons of the Drosophila brain.  J. Cell Sci. 126 Pt 12(): 2571--2576.

FBrf0221927

Research paper

In Drosophila, Insulin-like peptide 2 (Dilp-2) is expressed by insulin-producing cells in the brain, and is secreted into the hemolymph to activate insulin signaling systemically. Within the brain, however, a more local activation of insulin signaling may be required to couple behavioral and physiological traits to nutritional inputs. We show that a small subset of neurons in the larval brain has high Dilp-2-mediated insulin signaling activity. This local insulin signaling activation is accompanied by selective Dilp-2 uptake and depends on the expression of the Imaginal morphogenesis protein-late 2 (Imp-L2) in the target neurons. We suggest that Imp-L2 acts as a licensing factor for neuronal IIS activation through Dilp-2 to further increase the precision of insulin activity in the brain.