The neural underpinnings of vocal communication remain mostly unknown. The long-term goal of our laboratory is to elucidate the molecular signaling pathways important in vocal communication that are disrupted in neurodevelopmental disorders. Mutations in the gene encoding FOXP2 have previously been identified in individuals with speech and language disorders. In addition, FOXP2 transcriptionally regulates many genes involved in neurodevelopmental disorders such as autism and schizophrenia. Our preliminary studies have shown that expression of FOXP2 in the cerebellum is important for normal vocalizations and motor function. Moreover, we have uncovered a conserved site of post-translational modification of FOXP2 that it is important for gene expression regulation and motor function. Based on these data, the central hypothesis driving this proposal is that post-translational modification of FOXP2 is critical for regulating vocalizations and motor function. We propose to identify the role of post-transcriptional modification of FOXP2 on cerebellar-specific gene expression and motor function by manipulating Foxp2 expression in the mouse cerebellum through four specific aims: 1) Determine whether Foxp2 expression in the developing cerebellum is important for vocalizations and gene expression; 2) Assess the role of post-translational modification of Foxp2 on vocalizations; 3) Determine the role of post-translational modification of Foxp2 on gene expression; and 4) Assess the role of post-translational modification of Foxp2 on motor function. Together, these aims will determine the transcriptional program regulated by Foxp2 in the cerebellum and how Foxp2 gene regulation may be related to vocalizations and other motor-relevant behaviors. Completion of the proposed aims will provide increased knowledge as to the molecular pathways that can be targeted for treatment in individuals with communication disorders, cerebellar based motor disorders, and autism, which involves disrupted cerebellar function. These data will also provide insight into the basic molecular mechanisms governing normal brain development.