The cell cortex is a network of actin, myosin and associated proteins that lies under the plasma membrane and determines the shape of most animal cells. The cortex enables the cell to resist externally applied stresses and to exert mechanical work. As such, it plays a role in normal physiology during events involving cell deformation such as mitosis, cytokinesis, and cell locomotion, and in the pathophysiology of diseases such as cancer where cortical contractility is upregulated. Despite its importance, little is known about how the cortex is assembled and regulated.

As the cortex is an intrinsically mechanical structure (its biological activity results from its ability to contract and to exert forces), its physiological properties cannot be understood in isolation from its mechanics. The main focus of the group is to understand how these mechanical properties are determined by the molecular components of the cortex and how these properties are regulated, locally and globally, to drive cellular deformations. We particularly investigate the regulation of cellular mechanics during cytokinesis and cell migration. We combine biophysical and molecular approaches and focus on:

 

• the molecular basis of cortical mechanical properties,
• the mechanisms of formation of blebs, cellular protrusions directly resulting from cortical contractions,
• the role of cortex tension and blebs during cytokinesis,
• the formation and role of different types of protrusions during migration in vivo and in 3-dimensionnal environments.

Blebbing during cytokinesis in a mouse fibroblast (green: myosin-GFP).

A bleb induced by laser-ablation of the actin cortex (green: actin-GFP)

 

Blebs, lamellipodia and filopodia during cell migration in the zebrafish prechordal plate. (Red: plasma membrane; green: F-actin; scale bar = 10 um; time min:sec).
Collaboration with the Heisenberg lab.