The purpose of this National Research Service Award is to provide support to an individual for combined M.D./Ph.D. and other dual doctoral degree training. The goal of this research is to elucidate the role of neuroligins (NLs) in the formation of synapses, a process which is critical for the precise wiring of the nervous system and could be dysfunctional in ASD. One particular NL isoform, neuroligin 3, has been implicated in autism spectrum disorders. In this study, experiments will use a combination of cellular assays in dissociated hippocampal neurons, molecular biology approaches, and biochemical methods to probe protein-protein interactions between neuroligins and other synaptic proteins like neurexins and neurotransmitter receptors. The results obtained in the proposed experiments will yield a detailed functional characterization of NLs that will provide the basis for understanding cellular defects associated with autism spectrum disorders.