Spatiotemporal mapping of the tau interactome in human iPSC-derived neurons
Tara E. Tracy1,2, Danielle Swaney2,3, Michelle Moritz2, Michael E. Ward1,2,4, Ruth Hüttenhain2,3, Sang-Won Min1,2, Jordie Martin1,2, Chao Wang1,2, Peter Dongmin Sohn1,2, Yungui Zhou1, Nevan J. Krogan2,3, Li Gan1,2 1Gladstone Institute of Neurological Disease, San Francisco, CA; 2University of California San Francisco, San Francisco, CA; 3Gladstone Institute of Data Science and Biotechnology, San Francisco, CA; 4National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
Abnormal tau accumulation promotes toxicity in the brain in neurodegenerative diseases including Alzheimer's disease. Tau plays a critical role in disrupting neuronal function underlying cognitive decline in these diseases. Tau binds to and stabilizes the microtubule-based cytoskeleton, but less is known about what other tau-associated protein networks exist that could affect neuron function. The propagation of pathogenic tau across neural circuits in the brain may also involve the interaction of tau with a protein complex that regulates its active release from neurons. We developed an approach to investigate the tau interactome with spatial and temporal specificity using proximity-dependent biotin labeling by APEX, the engineered ascorbate peroxidase, and quantitative mass spectrometry. Human iPSC-derived glutamatergic neurons were genetically engineered to express tau fused to APEX, which catalyzes the biotinylation of neighboring proteins in close proximity during a 1 minute stimulation with hydrogen peroxide. Using this approach, we can uncover novel tau binding proteins that may contribute to pathogenic mechanisms in neurodegenerative disease.