An Integrative Analysis of the InR/PI3K/Akt Network Identifies the Dynamic Response to Insulin Signaling

Abstract

Insulin regulates an essential conserved signaling pathway affecting growth, proliferation and metabolism. To expand our understanding of the insulin pathway, we combine biochemical, genetic and computational approaches to build a comprehensive Drosophila InR/PI3K/Akt network. First, we map the dynamic protein-protein interaction network surrounding the insulin core pathway using bait-prey interactions connecting 566 proteins. Combining RNA interference screening and phospho-specific antibodies, we find that 47% of interacting proteins affect pathway activity, and using quantitative phosphoproteomics, we demonstrate that ~10% of interacting proteins are regulated by insulin stimulation at the level of phosphorylation. Next, we integrate these orthogonal datasets to characterize the structure and dynamics of the insulin network at the level of protein complexes, and validate our method by identifying regulatory roles for the Protein Phosphatase 2A (PP2A) and Reptin-Pontin chromatin-remodeling complexes as negative and positive regulators of ribosome biogenesis, respectively. Altogether, our study represents a comprehensive resource for study of the evolutionary conserved insulin network.