Neuron-specific protein network mapping of autism risk genes identifies shared biological mechanisms and disease relevant pathologies

There are hundreds of risk genes for autism spectrum disorder (ASD), but signaling networks at the protein level remain unexplored. We used neuron-specific proximity-labeling proteomics (BioID) to identify protein-protein interaction (PPI) networks for 41 ASD-risk genes. Neuron-specific PPI networks included synaptic transmission proteins, which are disrupted by de novo missense variants. The PPI network map revealed convergent pathways including mitochondrial/metabolic processes, Wnt signaling, ion channel activity and MAPK signaling. CRISPR knockout validations revealed an association between mitochondrial activity and ASD-risk genes. The PPI network showed an enrichment of 112 additional ASD-risk genes and differentially expressed genes from post-mortem ASD patients. Clustering of risk genes based on PPI networks identified gene groups corresponding to clinical behavior score severity. Our data reveal that cell type-specific PPI networks can identify previously unknown individual and convergent ASD signaling networks, provide a method to assess patient variants, and reveal biological insight into disease mechanisms and sub-cohorts of ASD. Cortices from Day 21-23 Taok2 WT and KO mice were used for RNA sequencing analysis, with 3 male mice per condition.