Anders Carlsson Seminar | Department of Biomedical Engineering

Speaker:
Anders Carlsson, Ph.D.
Department of Physics
NSF Center for Engineering MechanoBiology
Washington University in St. Louis

Title:
Force Generation in Biological Cells

Abstract:
Biological cells both generate and sense force. These processes impact a broad range of phenomena, ranging from cell migration to gene expression. One important role of force generation is to bend the cell membrane, when required for processes such as endocytosis. I will discuss physics-based simulation studies of two mechanisms by which membrane-bending forces can be generated. The first involves actin polymerization in the presence of inhomogeneous membrane chemistry. We find that a suitably chosen target pattern of membrane-bound proteins causes actin polymerization to generate a strong focus of pulling forces at the center. These forces can overcome opposing forces from membrane stiffness and osmotic pressure. The second is the assembly of asymmetrically shaped curvature-generating proteins (CGPs). We find, surprisingly, that the force-generating capability of a patch of CGPs increases as the patch gets smaller. For larger patch sizes, the forces form dipoles at the edge of the patch, which are inefficient for driving membrane bending.

Bio:
Anders Carlsson came to the Washington University Physics Department after receiving his Ph. D. in Physics from Harvard and performing postdoctoral work at Cornell University. He has previously performed research in several areas of the theory of condensed matter, including the properties of quasicrystals and brittle vs. ductile behavior of materials. Since then his research has been in biological physics. He is currently working on understanding the mechanisms underlying force generation in biological cells, which is crucial for cell shape changes and migration. Within this field, he has a focus on understanding the mechanisms of endocytosis in yeast. He was Jubilee Professor at the Chalmers University of Technology in Gothenburg in 2001, spent the fall of 2008 as a visitor at the Max Planck Institute for the Physics of Complex Systems in Dresden, and is a member of the NSF Center for Engineering Mechanobiology.