A molecular probe that stores and integrates short-lived cellular mechanical events over time.
- Quantitative method of measuring short-lived interactions between cells.
- Ideal for immunology-based assays
- Fluorescence-based and amenable as a drug screening research tool.
Studying the interplay between mechanical forces and chemical signaling in living cells is challenging. This is, in part, because it involves the transmission of forces which are often weak, infrequent, and short lived, and hence difficult to study. Such rare mechanical events are especially important for the immune system, where ligand–receptor bindings are short-lived and a few molecules are sufficient to trigger a response. These events have a wide range of applications like platelet activation, T cell and B cell receptor triggering, as well as cell adhesion and migration. There is a significant need to develop new probes to detect infrequent or short-lived mechanical events actively generated by cells.
Emory researchers solved this challenge by developing a molecular tension-based fluorescence microscopy (MTFM) system to create a real-time map of the forces exerted by live cells. MTFM probes are anchored to a surface and composed of a spring-like element flanked by a fluorescent molecule and presenting a biological ligand for receptor recognition. In the absence of any binding there is no fluorescence. Upon binding to a receptor or other interacting molecule, the fluorescent molecule activates and the strength of the signal can be correlated to the force exerted. This strategy allows for integration and storage of mechanical information into a map of molecular tension history. This system was used to examine the T cell receptor (TCR) forces when encountering different antigens and investigate the T cells transmitting forces to the co-inhibitory receptor, programmed cell death receptor 1 (PD1).
The mechanical recording assay was successfully validated in primary T cells.
Publications: Ma, R. et al. (2019). PNAS, 116(34), 16949-54.