Molecular Tension Probes for Imaging Forces at the Cell Surface

Area of Science:

• Biophysics
• Cell Biology
• Biochemistry

Background:

• Mechanical forces regulate critical cellular processes like transcription, translation, and cell migration.
• Mechanotransduction, the process by which cells sense and respond to physical stimuli, is mediated by cell membrane receptors.
• Existing methods like Traction Force Microscopy (TFM) and Single Molecule Force Spectroscopy (SMFS) have limitations in throughput and force sensitivity.

Purpose of the Study:

• To introduce Molecular Tension Fluorescence Microscopy (MTFM) as a novel tool for imaging receptor mechanics in living cells.
• To review MTFM probe design, including extendable linkers, fluorophore-quencher pairs, immobilization chemistry, and ligand strategies.
• To discuss the strengths and weaknesses of MTFM through case studies of signaling pathways.

Main Methods:

• Development and application of Molecular Tension Fluorescence Microscopy (MTFM).
• MTFM probes utilize extendable linkers (polymers, oligonucleotides, proteins) with fluorophore-quencher pairs to measure force.
• Fluorescence emission is measured to infer linker extension and applied force, providing piconewton (pN) sensitivity.

Main Results:

• MTFM optically reports receptor forces across the cell surface with pN sensitivity, combining advantages of TFM and SMFS.
• Case studies demonstrate MTFM's application in analyzing forces within epidermal growth factor receptor, integrin, and T-cell receptor signaling pathways.
• The study provides an in-depth review of MTFM probe design considerations.

Conclusions:

• MTFM is an emerging tool that overcomes previous limitations in measuring cell receptor forces.
• This technique offers a powerful approach for elucidating the molecular mechanisms of mechanotransduction.
• Future developments in MTFM probe design hold significant promise for advancing cell mechanics research.