Project Summary Neurofibromatosis type 1 is a relatively common monogenetic, multisystemic disorder that affects approximately one in 3,500 individuals worldwide. The causative gene encodes a protein called neurofibromin (Nf1), which essentially acts as a brake on Ras signaling via Ras-GAP activity. Nf1 affects multiple downstream signaling cascades, including central regulators of metabolism. Prior studies have suggested that loss of Nf1 may affect metabolism, but the mechanisms, particularly at the systemic level are unclear. Nf1 effects on metabolic processes may underlie or modulate some of the symptoms of the disease, such as behavioral alterations and cancer predisposition. This project will test the mechanisms underlying how loss of Nf1 affects metabolism in vivo, using the powerful Drosophila model for neurofibromatosis type 1. Upon completion, we will have a clear picture of: (1) the genes and cellular signaling cascades that regulate metabolism in an Nf1- dependent manner, (2) how Nf1 functions in neuronal circuits to regulate metabolism through central control, (3) the neurotransmitters and/or peptides that are involved in the central control of metabolic regulation, (4) how loss of Nf1 mechanistically regulates peripheral energy stores through the effects of novel genes. The highly conserved nature of Nf1 and its signaling functions, as well as fundamental neuronal circuit functional principles, underscores the broad applicability of the results. Overall, this project will contribute to understanding conserved Nf1 functions in metabolism and neuronal function, laying the foundation for research into metabolic effects of Nf1 across organisms and future development of novel therapeutic interventions.