Browsing by Author "Keren, Kinneret"

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    Roadmap for the multiscale coupling of biochemical and mechanical signals during development
    (IOP Publishing, 2021) Lenne, Pierre-François; Munro, Edwin; Heemskerk, Idse; Warmflash, Aryeh; Bocanegra-Moreno, Laura; Kishi, Kasumi; Kicheva, Anna; Long, Yuchen; Fruleux, Antoine; Boudaoud, Arezki; Saunders, Timothy E.; Caldarelli, Paolo; Michaut, Arthur; Gros, Jerome; Maroudas-Sacks, Yonit; Keren, Kinneret; Hannezo, Edouard; Gartner, Zev J.; Stormo, Benjamin; Gladfelter, Amy; Rodrigues, Alan; Shyer, Amy; Minc, Nicolas; Maître, Jean-Léon; Talia, Stefano Di; Khamaisi, Bassma; Sprinzak, David; Tlili, Sham
    The way in which interactions between mechanics and biochemistry lead to the emergence of complex cell and tissue organization is an old question that has recently attracted renewed interest from biologists, physicists, mathematicians and computer scientists. Rapid advances in optical physics, microscopy and computational image analysis have greatly enhanced our ability to observe and quantify spatiotemporal patterns of signalling, force generation, deformation, and flow in living cells and tissues. Powerful new tools for genetic, biophysical and optogenetic manipulation are allowing us to perturb the underlying machinery that generates these patterns in increasingly sophisticated ways. Rapid advances in theory and computing have made it possible to construct predictive models that describe how cell and tissue organization and dynamics emerge from the local coupling of biochemistry and mechanics. Together, these advances have opened up a wealth of new opportunities to explore how mechanochemical patterning shapes organismal development. In this roadmap, we present a series of forward-looking case studies on mechanochemical patterning in development, written by scientists working at the interface between the physical and biological sciences, and covering a wide range of spatial and temporal scales, organisms, and modes of development. Together, these contributions highlight the many ways in which the dynamic coupling of mechanics and biochemistry shapes biological dynamics: from mechanoenzymes that sense force to tune their activity and motor output, to collectives of cells in tissues that flow and redistribute biochemical signals during development.
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    Self-organized stress patterns drive state transitions in actin cortices
    (AAAS, 2018) Tan, Tzer Han; Malik-Garbi, Maya; Abu-Shah, Enas; Li, Junang; Sharma, Abhinav; MacKintosh, Fred C.; Keren, Kinneret; Schmidt, Christoph F.; Fakhri, Nikta; Center for Theoretical Biophysics
    Biological functions rely on ordered structures and intricately controlled collective dynamics. This order in living systems is typically established and sustained by continuous dissipation of energy. The emergence of collective patterns of motion is unique to nonequilibrium systems and is a manifestation of dynamic steady states. Mechanical resilience of animal cells is largely controlled by the actomyosin cortex. The cortex provides stability but is, at the same time, highly adaptable due to rapid turnover of its components. Dynamic functions involve regulated transitions between different steady states of the cortex. We find that model actomyosin cortices, constructed to maintain turnover, self-organize into distinct nonequilibrium steady states when we vary cross-link density. The feedback between actin network structure and organization of stress-generating myosin motors defines the symmetries of the dynamic steady states. A marginally cross-linked state displays divergence-free long-range flow patterns. Higher cross-link density causes structural symmetry breaking, resulting in a stationary converging flow pattern. We track the flow patterns in the model actomyosin cortices using fluorescent single-walled carbon nanotubes as novel probes. The self-organization of stress patterns we have observed in a model system can have direct implications for biological functions.