Project C.5: Cell morpho-dynamics driven by actin polymerization

The morpho-dynamics exhibit random transient protrusions, steady non-propagating protrusions, propagating protrusions and homogeneous oscillations. They are controlled by a variety of pathways, in particular small Rho-GTPases. The recent progress in measuring spatio-temporal GTPase activity revealed a large variety of activation patterns and questions traditional views on the function of individual GTPases. Additionally, the effect of signaling in terms of parameters of the actin polymerization dynamics is often not known. The ability to assign states of the actin polymerization parameters to observed morpho-dynamic patterns would be a valuable tool in the exploration of the pathways. The project will tackle this task by investigating the conditions for the variety of patterns with mathematical modeling. The basis is a model which has proven its relevance by quantitatively reproducing the dynamic motility of protein coated oil drops, beads, the morpho-dynamic phenotypes and by quantitatively establishing the mechanism of the force-velocity relation of fish keratocytes. Recent application to oscillations achieved also quantitative agreement with the variables reported in experimental studies.
The project is a comprehensive bifurcation analysis of the spatio-temporal mechanochemical system and simulations of a spatially extended implementation of the most recent state of the local dynamics. The simulations describe the dynamics of the cell contour, which we will supplement by diffusion of signaling molecules in the bulk. This setup will allow for an analysis of the variety of generation and propagation mechanisms currently discussed and beyond.

Project leaders: Prof. Dr. M. Falcke [1], Prof. Dr. H. Engel [2], Prof. Dr. C. Beta [3]