Centre de Physique Théorique


Wednesday 9 October 2019

16h00 – 17h00, Amphi 5 du CPT

Molecular to cellular mechanics using high-speed force spectroscopy

Felix Rico (LAI, Aix Marseille Univ / Inserm / CNRS)

Complete understanding of cell mechanics requires probing also the mechanical properties of individual proteins, filaments, and molecular complexes, since these provide structural stability and mechanical flexibility to the living cell. Moreover, the dynamical response of biological systems at the nano- and microscales span over several orders of magnitude in time. Thus, access to a wide range of length and time scales is required to decipher the molecular determinants of cell mechanics. High-speed atomic force microscopy (HS-AFM) is a unique technology allowing subsecond, nanometric imaging[1]. We have adapted HS-AFM to perform high-speed force spectroscopy (HS-FS) probing protein unfolding and receptor/ligand unbinding up to the velocity of molecular dynamics simulations[2–5]. This combination provides atomistic understanding of biomolecular processes based on experimental results. Our recent results revealed heterogeneous and rate dependent unfolding and unbinding pathways on different biomolecules. We have also developed high-frequency microrheology (HFMR) to probe the mechanics of cells at high frequencies, up to 100 kHz[6]. We report the viscoelastic response of different cell types and upon cytoskeletal drug treatments. At a few microsecond timescales, cells exhibit rich viscoelastic responses that depend on the state of the cytoskeleton and on the cell type. Mechanical measurements over the widest dynamic range provide mechanistic understanding of molecular and cellular mechanics allowing direct evaluation of theoretical predictions.


[1] T. Ando, N. Kodera, E. Takai, D. Maruyama, K. Saito, A. Toda, A high-speed atomic force microscope for studying biological macromolecules, PNAS 98 (2001) 12468–12472.
[2] F. Rico, L. Gonzalez, I. Casuso, M. Puig-Vidal, S. Scheuring, High-Speed Force Spectroscopy Unfolds Titin at the Velocity of Molecular Dynamics Simulations, Science 342 (2013) 741–743.
[3] F. Sumbul, A. Marchesi, H. Takahashi, S. Scheuring, F. Rico, High-Speed Force Spectroscopy for Single Protein Unfolding, in: Y.L. Lyubchenko (Ed.), Nanoscale Imaging: Methods and Protocols, Springer New York, New York, NY, 2018: pp. 243–264.
[4] H. Takahashi, F. Rico, C. Chipot, S. Scheuring, α-Helix Unwinding as Force Buffer in Spectrins, ACS Nano. 12 (2018) 2719–2727.
[5] F. Rico, A. Russek, L. González, H. Grubmüller, S. Scheuring, Heterogeneous and rate- dependent streptavidin–biotin unbinding revealed by high-speed force spectroscopy and atomistic simulations, PNAS. 116 (2019) 6594–6601.
[6] A. Rigato, A. Miyagi, S. Scheuring, F. Rico, High-frequency microrheology reveals cytoskeleton dynamics in living cells, Nat Phys. 13 (2017) 771–775.