A7.2023: The role of intermediate filaments in composite cytoskeletal networks at high strains

Lead PI: Sarah Köster

Collaborating PIs: Andreas Janshoff, Helmut Grubmüller, Anne Wald, Stefan Klumpp, Peter Sollich

Overarching research question: How does the non-linear behavior of IFs influence cytoskeletal network mechanics?

Among the different cytoskeletal biopolymers, intermediate filaments exhibit highly non-linear behavior at strains above 10%. This interesting mechanical behavior is closely related to the non-equilibrium unfolding of protein structures. Intermediate filaments are linked to F-actin and microtubules by binding proteins (e.g. plectins), ionic, or steric interactions, and by these interactions, intermediate filaments may contribute to the mechanical response of the active cytoskeleton. Here, we choose an in vitro approach to study intermediate filaments in the context of composite cytoskeletal networks and will complement this passive biopolymer network with active molecular motors. We employ several different methods to exert high strains on the networks, including optical tweezers, microfluidics, and atomic force microscopy, and investigate to which extent the non-linear mechanics of the intermediate filaments influence network mechanics. These studies will enable a better understanding of the intricate composite nature of the cytoskeleton when mechanically strained.

Core field: experimental biophysics

PhD training objectives: biophysical characterization methods (imaging, optical tweezers, AFM, microfluidics); microfluidics; biochemical methods (protein purification, handling, labeling); data analysis (image processing, force-strain data); modeling (Monte Carlo simulations).