Elucidating mechanisms of the protein-based material underlying cellular movement.

Friday, January 31, 2014 - 2:00pm
Fung Auditorium | Powell-Focht Bioengineering Hall
Margaret Gardel, Ph.D.

Associate Professor of Physics

University of Chicago

Elucidating mechanisms of the protein-based material underlying cellular movement.

The cytoskeleton of living cells is a quintessential example of active matter, in which internal molecular processes transduce chemical energy into local stresses that drive structural rearrangements and dominate its material response.  The physical behaviors of such “living matter” engender cells with the ability to move, divide and build multi-cellular tissue.  Across diverse physiological processes, an important class of cytoskeletal materials includes those that generate contractile forces.  At the nano-meter (molecular) scale, mechanical stresses are generated by the translocation of myosin II motors along semi-flexible polymers of actin. However, how these molecular scale interactions guide the emergent self-organization and behaviors of contractile matter at micro-meter (cellular) to milli-meter (tissue) length scales is unknown.  We have utilized high resolution imaging and force spectroscopy approaches to characterize the actomyosin networks formed in living cells as well as in contractile bundles and networks reconstituted from purified proteins.  With the assistance of analytical theory and simulation, we seek to understand the fundamental physical principles of active contractile matter.   Our results identify the importance of the nonlinear elastic response of actin filaments as a robust means of symmetry breaking.  Moreover, our results demonstrate a mechanism to mechanically coordinate contractility with actin polymerization dynamics.  General principles of the self-organization and force transmission of actomyosin bundles and networks found in living cells emerge from these findings.

Margaret Gardel is an Associate Professor of Physics in the Department of Physics at the University of Chicago.  She received her Ph.D. in Condensed Matter Physics at Harvard University in 2004 and then was a postdoctoral fellow in Cell Biology at the Scripps Research Institute.  Her lab focuses on elucidating the emergent physical properties of the actin cytoskeleton and how these regulate cell adhesion, shape and force generation by integrating approaches from cell biology, materials science, physics and biochemistry. She is a recepient of an NIH Pioneer Award, Packard Fellowship, Sloan Fellowship, American Asthma Foundation Early Excellence Award and Burroughs Wellcome Career Award.