MAE Seminar – Michael Murrell – Active Stress Coordinates Steady States and Contractile Flows in the Actomyosin Cell Cytoskeleton

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4:00 pm-5:00 pm
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303 MAE-A


Active Stress Coordinates Steady States and Contractile Flows in the Actomyosin Cell Cytoskeleton

Michael Murrell, Assistant Professor
Biomedical Engineering Department, and the
Systems Biology Institute, Yale West Campus

While the molecular interactions between myosin motors and F-actin are well known, the relationship between F-actin organization and myosin-mediated force generation remains poorly understood. Here, we explore the accumulation of myosin-induced stresses within a 2D biomimetic model of the actomyosin cortex, where myosin activity is controlled spatially and temporally using light. By controlling the geometry and the duration of myosin activation, we show that the transition from stability to contractility in disordered actomyosin is highly cooperative, telescopic with the activation area and generates a pattern of mechanical stresses consistent with those observed in contractile cells. We quantitatively reproduce these properties using an in vitro isotropic model of the actomyosin cytoskeleton, and explore the physical origins of telescopic contractility and stability in disordered networks using agent-based simulations.

Michael Murrell is an Assistant Professor in the Biomedical Engineering Department, and the Systems Biology Institute at the Yale West Campus. Murrell received his B.S. from Johns Hopkins University in Biomedical Engineering and his PhD from the Massachusetts Institute of Technology in Bioengineering working for Paul Matsudaira and Roger Kamm. He then pursued his postdoctoral studies jointly with Margaret Gardel at the University of Chicago, and Cecile Sykes at the Institut Curie in Paris, France.

Murrell’s interests are in understanding the mechanical principles that drive major cellular life processes through the design and engineering of novel biomimetic systems. To this end, he develops simplified and tractable experimental models of the mechanical machinery within the cell with the goal of reproducing complex cellular behavior, such as cell division and cell migration. Murrell then combines these ‘bottom-up’ experimental models with concepts from soft matter physics to gain a fundamental understanding of the influence of mechanics on cell and tissue behavior. In parallel, he hopes to identify new design principles from biology which can be used to create novel technologies.