Understanding the Role of Autism Associated Kinase BRSK2 in Neurodevelopment and Disease

Abstract ID 99559 Poster Board 131 Neuronal development is mediated by intricate kinase signaling networks that orchestrate different stages from the begining of neurogenesis to maturation of the synaptic network. Aberrant kinase signaling leads to neurodevelopmental disorder,intellectual disability, and autism spectrum disorders (ASD). Clinical data and several exome sequencing studies reveal that Brain Selective Kinase 2 (BRSK2) is one such serine/threonine kinase associated with autism. Previous studies in animal models have shown that it plays important roles in distinct stages of axon development and neuronal polarity. However, BRSK2 remains as a relatively understudied kinase in neuropathogenesis. To investigate the effect of the ASD related mutations in the function and regulation of BRSK2 in the context of neurodevelopment, I generated BRSK2 expression constructs harboring autism associated mutations through site directed mutagenesis. Using in vitro kinase assays, I found that ASD related mutations in the kinase domain of BRSK2 such as missense variants E66K, A163V, and G212E are catalytically deficient. Further, through affinity purification of wild type GFP-BRSK2 or endogenous BRSK2, I found that BRSK2 is subject to major post translational modifications via phosphorylation. To identify in an unbiased fashion the direct substrates of BRSK2 in the brain, I will use a chemical-genetics approach where the gatekeeper residue (insert amino acid number) is mutated to a smaller amino acid Ala or Gly. Using the engineered analog-sensitive BRSK2 mutant, I will screen bulky ATP¥S analogs in order to find the optimal condition where only the analog-sensitive BRSK2 but not the wildtype can utilize the spiked analog. This will allow me to covalently capture putative BRSK2 substrates from brain lysate and identify them using mass spectrometry. With a combination of biochemical approaches, chemical-genetics and using human stem cell derived models we aim to determine mechanisms through which BRSK2 mediates neurodevelopment and how ASD-associated mutations in BRSK2 contribute to neurodevelopmental disordes.