Project Summary Profiling kinases and their activities in single cells will enable exploration of cell type specific functional and biochemical pathways. While we have learned a great deal about transcriptional states of different cell types in the past decade through single cell genomics, we still understand little about proteins and in particular kinases networks in diverse cell populations. This is largely because single-cell kinome analysis faces major technical challenges. Unlike nucleic acids, proteins cannot be amplified, making detection of minute quantities from single cells difficult. We recently demonstrated a proof-of-principle experiment to accurately detect protein PTM isoforms in single cells. Here we propose to scale this method up to profile kinases at the global level in single cells in both cell culture and in tissues. We will integrate the single cell kinome analysis with RNA measurements to identify cell type specific kinase profiles. Ultimately, we will map the kinome with spatial context in the mouse and human brain to examine the kinase pathways involved in aging and neurodegeneration which could identify druggable targets. This project is a major departure from our current research. Its goals are ambitious but achievable. The project will leverage our expertise in single cell technology development and in application of new technology to diverse biological systems.