Host: Stefan Diez (B CUBE)
Title: \"How t o be squishy and protective at the same time – the physics of biological matter\"
Abstract: The tissues in our body have a stonishingly varying mechanical and dynamic properties\, that are perfectl y adapted to their function: muscle cells actively contract\, immune cells are highly motile\, and cells in the skin or lung form stable\, highly co nnected ensembles. Importantly\, biological cells and tissues possess elas tic\, solid-like properties and viscous\, liquid-like properties at the sa me time. These viscoelastic mechanics are to a great part determined by th e cytoskeleton\, a composite biopolymer network composed of three filament systems – intermediate filaments\, actin filaments and microtubules – along with cross-linkers and molecular motors.
Intermediate filame nts are more flexible and much more extensible than the other cytoskeletal filaments\, including an intriguing non-linear behavior. Using optical tw eezers\, we have characterized the response to pulling of two types of int ermediate filaments (vimentin and keratin) that play an important role in\ , e.g.\, cancer metastasis. We were able to model this response by taking into account the strictly hierarchical build-up of the filaments. This uni que architecture consists of multiple alpha-helical domains arranged in pa rallel and non-equilibrium transitions between folded and un-folded states . Combining the experiments and the model we conclude that intermediate fi laments serve as “safety belts” and „shock absorbers” for the cell \, thus avoiding damage at high\, fast impact\, while maintaining flexibil ity\, e.g.\, during cell motility. We also unravel distinctly different be haviors of keratin versus vimentin filaments\, in line with their roles in stationary and motile cells\, respectively.
DTSTAMP:20260710T164401Z CREATED:20240725T053537Z LAST-MODIFIED:20240904T053803Z END:VEVENT END:VCALENDAR