Anders Carlsson
Department of Physics
Washington University
St. Louis, MO 63130
(314) 935-5739
aec@wuphys.wustl.edu
FAX: (314) 935-6219
Anders has been at Washington University since 1983, and is
Professor of Physics. His research interests are focused on
modeling the polymerization processes underlying the crawling
motions of cells. This work is being performed in collaboration
with Professors
John Cooper at the
Washington University School of Medicine and
David Sept in the Washington University Department
of Biomedical Engineering. The motions
of cells, extensions of their boundaries, and cell division
often involve polymerization and depolymerization of the protein
actin. This protein forms long, fairly stiff filaments, whose growth
can supply the mechanical force necessary for cell motion or shape
changes. The filaments are often found in branched or cross-linked
networks. The distribution of actin inside cells displays spontaneous
dynamic behavior which is similar to that of an excitable medium.
The modeling work treats these phenomena with methods
including Brownian-dynamics and stochastic-growth simulations,
and analytic theory. The main goals of the modeling are to
are to understand how the structures formed by actin filaments
respond to external stimuli, to establish how the structure of the
networks is determined by the activities of cross-linking proteins, to
pin down the main energetic factors underyling actin bundling,
and to establish how the cell cytoplasm functions as an excitable
medium.
Shown above is the structure of an "actin tail" obtained by computer simulation.
Take a look at a movie of two
actin filaments trying to bundle or one of the
growth of
an actin filament attached to an obstacle. These movies are obtained from Brownian
dynamics simulations by Le Yang and Jie Zhu, and the work is supported by the
National Science Foundation under Grant DMS-0240770.
Recent preprints:
Effects of Hydrolysis on Force Generation by Actin Filaments
Actin Polymerization Overshoots and Hydrolysis as Assayed by Pyrene Fluorescence
