Neurofibromin, the product of the NF1 gene, is one of a family of GTPase-activating proteins (GAPs) that accelerate hydrolysis of active Ras-GTP to inactive Ras-GDP. Loss of neurofibromin (through mutations in NF1) causes a failure to terminate Ras signals and increases levels of active Ras. Our lab has previously shown that Schwann cells cultured from human neurofibromas have high levels of active Ras. Additionally, we've shown that an FPTI (a drug that inhibits some Ras processing) obtained from Merck Research Laboratories inhibits growth of NF1 mutant Schwann cells, and colleagues showed that this was also true for MPNST cells. Not only did these results suggest the possible efficacy of FPTIs in treatment of NF1 (currently in clinical trials for plexiform neurofibromas in the NF1 Clinic at Cincinnati Children's Hospital Medical Center), but these results also provide evidence of a key role for Ras signaling in the development of neurofibromas and MPNSTs. There are many different members of the Ras protein family that can affect different cellular responses. Our lab is interested in elucidating the role of Ras proteins in the development of neurofibromas / MPNST.