Biomimetism of cellular movement
The group aims to understand how cells move, with the long-term perspective of a better understanding of the cell movements involved in cancer metastasis. We develop biomimetic systems and simplified cellular models that reproduce specific aspects of cell movement under controlled conditions. Using this approach, we can study the physical and biochemical mechanisms governing cell movement and cell shape changes. The group has 3 complementary strategies: study of the actomyosin cytoskeleton-membrane system using simple cells and cellular mimics (Sykes Team), the biochemical characterization of biopolymer (actin and Major Sperm Protien) dynamics in vitro and in cells and tissues (Plastino Team), and the analysis and modeling of the mechanical properties of cellular and biomimetic systems (Betz Team).
The main research lines:
Bead systems: We design biomimetic systems where actin polymerization is reproduced in a controlled fashion on surfaces by coating with actin polymerization activators. The objects are then incubated in cell extracts or in pure protein mixes and the actin structures that grow from the surfaces mimic cellular filamentous actin. This set-up lends itself to quantitative measurements and physical characterization as parameters can be varied, such as the size and deformability of the beads, the composition of the protein mix and the nature and density of the coating. Thus we can test the physical and biochemical properties of actin polymerization in order to better understand how polymerization produces motility.
Liposome systems: In order to more closely mimic the living cell, we have developed systems composed of liposomes filled with the minimum motility components. Actin polymerization activators are attached to the inner leaflet of the lipid bilayer of artificial liposomes, and the interior of the lipsosome is filled with the ingredients necessary for actin polymerization. We have succeeded in forming a dynamic actin cortex. This system provides a simplified and controlled model of cellular actin polymerization at the membrane.
- Reconstitution of the actin cortex
- Shiga toxin entry into cells
- Mechanical measurements of the actin cortex
Cells Mechanics and motility: We complement our in vitro studies with the study of simple cellular and tissular systems. The use of biomimetic systems together with living systems will allow us to compare the characteristics and quantify the mechanics and dynamics of cell shape changes.
- Oscillation of cell fragments
- Cytoskeleton membrane interaction in red blood cells
- MSP dynamics in C. elegans sperm cells