We have gathered strong evidence that the synaptotoxicity of prions depends on activation of specific signaltransduction pathways that cause changes in protein phosphorylation mediated by key protein kinases, andthat result in downstream alterations in gene transcription. In this project, we propose to use cutting-edgeproteomic techniques and RNA-Seq to analyze global changes in protein phosphorylation and genetranscription in neurons undergoing the earliest detectable changes in synaptic structure and function. We willuse specialized cultures of hippocampal neurons that respond rapidly (within hours) to neurotoxic forms ofPrPSc by retraction of dendritic spines and by alterations in synaptic transmission. We then plan to processthese data using sophisticated bioinformatics pipelines to identify cellular signaling pathways andtranscriptional networks mediating the synaptotoxic effects of PrPSc. We anticipate that the comprehensive,discovery-based approach outlined here will yield important clues to the underlying biology of prion diseases,and will identify a wealth of novel therapeutic targets for ameliorating synaptic degeneration in these disorders.