Molecular to cellular mechanics probed by high-speed atomic force microscopy
Felix Rico (Aix-Marseille Université)
The mechanical properties of individual proteins, filaments, and supramolecular assemblies provide structural stability and mechanical flexibility to the living cell. Thus, molecular understanding of the mechanics from the single molecule to the whole cell is relevant to understand biological function. High-speed atomic force microscopy (HS-AFM) is a unique technology that combines nanometric-imaging capabilities at video rate. In this talk, I will present our recent applications of HS-AFM to probe protein and cellular mechanics. In the first part, I will introduce the development of high-speed force spectroscopy (HS-FS) to probe protein unfolding at the timescales of molecular dynamics simulations (1). This provides a unique approach to acquire atomistic understanding of biomolecular processes based on experimental results. In the second part, I will present our recent work on the adaptation of HS-AFM to probe the microrheology of living cells at high frequencies (up to 100 kHz), revealing cytoskeletal dynamics (2). We show that the mechanical response at high frequencies depends on the actin filament tension and pathological state of the cell. Microrheology over a wide dynamic range—up to the frequency characterizing the molecular components—provides a mechanistic understanding of cell mechanics.
1. 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, 741 (2013).
2. A. Rigato, A. Miyagi, S. Scheuring, F. Rico, High-frequency microrheology reveals cytoskeleton dynamics in living cells. Nat Phys 13, 771 (2017).