Professor Jay X. Tang
Physics Dept & Indiana Molecular Biology Institute
Indiana University at Bloomington
Bloomington, Indiana

Monday, October 28, 2002
3:00 pm (CT)
3269 Beckman Institute

Abstract

The hierarchical and dynamic assembly of actin plays essential roles in many aspects of cellular locomotion. The polymerization of the globular protein G-actin to form long filaments (F-actin) has been modeled as a condensation phenomenon, and the energy release is coupled to force generation and motility. At physiological concentrations, F-actin can form both liquid crystalline and paracrystalline states, driven by both entropic effects and solution electrostatics. These physical properties are clearly important to many cytoskeletal functions of the actin network, although a number of accessory actin binding proteins are also required for various functions, including motility. For example, a reconstituted in-vitro system of protein-coated micro-sized beads in a multi-component protein broth results in constant movement of the beads, pushed by the so-called "comet tails" generated by the actin assembly. We recently started to analyze and model surprising new observations of the actin tail motility in such a reconstituted system, which we hope will shed light on how force and motions are generated by a protein assembly.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.