Bioorthogonal Photocatalytic Profiling of Mitochondrial Proteomes from Primary Living Samples. CAT-S Proteomic Dataset.
In situ profiling of subcellular proteomic networks in primary and living systems, such as primary cells from native tissues or clinic samples, is crucial for the understanding of life processes and diseases, yet challenging for the current proximity labeling methods (e.g., BioID, APEX) due to their necessity of genetic engineering. Here we report CAT-S, an up-to-date bioorthogonal photocatalytic chemistry-enabled proximity labeling method, that expands proximity labeling to a wide range of primary living samples for in situ profiling of subcellular proteomes. Powered by the newly introduced thioQM labeling warhead and targeted bioorthogonal photocatalytic decaging chemistry, CAT-S enables labeling of mitochondrial proteins in living cells with high efficiency and specificity (up to 87%). We applied CAT-S to distinct cell cultures, mouse tissues as well as primary T cells from human blood, portraying the native-state mitochondrial proteomic characteristics, and unveiled a set of hidden mitochondrial proteins in human proteome. Furthermore, CAT-S allowed quantitative analysis of the in situ proteomic perturbations on dysfunctional tissue samples, exampled by diabetic mouse kidneys, and revealed the alterations of lipid metabolism machinery that drive the disease progression. Given the advantages of non-genetic operation, generality, efficiency as well as spatiotemporal resolution, CAT-S may open new avenues as a proximity labeling strategy for in situ investigation of subcellular proteomic landscape of primary living samples that are otherwise inaccessible.