Mechano-ID: proximity labeling of mechanically active receptors and cells

A major challenge in the field of mechanobiology relates to the lack of methods that enable identification of mechanically active cells and force transmitting receptors for subsequent biochemical analysis. For example, potent T cell activation requires the transmission of biophysical forces between the T cell receptor (TCR) and its peptide-loaded major histocompatibility complex (pMHC) antigens. Therefore, methods that can chemically tag mechanically active T cells and TCRs are highly desirable, as these techniques will enable a deeper understanding of the mechanisms governing immune responses and may also have broad applications in immunotherapy. Herein, we report a technique dubbed mechano-ID, which allows for mechanically selective proximity tagging by leveraging DNA-based molecular force probes that recruit proximity tagging enzymes. We demonstrate mechano-ID tagging of T cells using microscopy and flow cytometry and this is further confirmed using western blotting of mechanically active T cell receptors.