1.Title : Computational studies of rheology and mechano-sensing of actin cytoskeleton

2.Speaker : Dr. Taeyoon Kim

                Postdoctoral Associate, Institute for Biophysical Dynamics,

                University of Chicago

3.Schedule : Aug 30th (Thu) 11:00~12:00

4.Venue : Rm.1512-2, Bldg.301

5.Abstract :

The actin cytoskeleton is the scaffolding structure of eukaryotic cells, providing structural integrity, resistance to deformation, and adaptation to diverse external stimuli. It consists mainly of actin filaments cross-linked by passive cross-linking proteins with molecular motors that generate contractile forces. The actin cytoskeleton plays a crucial role in numerous cellular processes such as migration, mitosis, and contraction. Computational models can be used to gain insight into the mechanics of the cytoskeleton. Such models have the potential to help interpret experimental measurements and to generate and test hypotheses regarding the underlying physics that determines cell rheological properties. We developed a rigorous computational model via Brownian dynamics and C language, which is parallelized for supercomputing. In the model, the major constituents of actin cytoskeleton are coarse-grained by cylindrical elements and interact via energetic potentials and specific kinetics. We have shown how the mechanical and dynamic properties of the components in microscopic scale determine the rheological behaviors of actin cytoskeleton in macroscopic scale through several stages: a) a network with permanent cross-links, b) a dynamic network in which the cross-links can both break/reform and fold/unfold, and c) a network that contains both dynamic cross-links and active motors. These results will be presented for each level of model complexity, addressing linear and nonlinear behavior, plastic deformations, and the molecular origins of each. In addition, our model elucidates how cells sense external mechanical environments such as substrate stiffness. In sum, our studies provide insights into the detailed origin of network rheology and help to explain the fundamental basis for cell mechano-sensing.

 

6.Bio :

Ph.D. Mechanical Engineering, Massachusetts Institute of Technology, 2010.

M.S. Mechanical Engineering, Massachusetts Institute of Technology, 2007.

B.S. Mechanical Engineering, Seoul National University, 2004.

University of Chicago, Postdoctoral Associate, Jan 2011 - present.

Massachusetts Institute of Technology, Postdoctoral Associate, Oct 2010 - Dec 2010.

Massachusetts Institute of Technology, Graduate Research Assistant, Sep 2005 - Sep 2010.

 

※ Contact :  Prof. Maenghyo Cho (880-1703)