Guillaume Salbreux: Projects

Cell mechanics and the cytoskeleton

We are interested in understanding the cell cortex, a network of actin filaments and myosin molecular motors located at the surface of the cell, which plays a key role in numerous cellular processes. Using coarse-grained theories of the cytoskeleton, we ask how forces generated in the cortex play a role in cell migration, cell division and in interkinetic nuclear migration, the process by which the cell nucleus moves to the apical side of an epithelial cell prior to cell division.

We are also interested in the mechanical coupling between the membrane and the cellular actin cortex and its influence on cell mechanics. Little is understood about how the actin cytoskeleton at the cell surface mechanically constraints the lipid membrane. Recent experiments have shown that the cell membrane can adopt surprisingly complex folded shapes, presumably due to its attachment to cortical filaments. We develop models to describe the shape and mechanical state of the cell membrane, incorporating forces exerted by the cytoskeleton, as well as knowledge on mechanisms regulating the cell membrane surface area.

Tissue mechanics in 2D and 3D

The primary goal of morphogenesis is to establish animal shape. Dramatic tissue deformations occur during morphogenesis, such as invagination of epithelia, formation of furrows and tissue growth and shrinkage. These events are controlled by patterns of gene expression but are also powered by mechanical forces that induce transient deformations, as well as maintain the shape of cells and tissues over long time scales.

In order to understand the deformations of tissues in 3D, we have developed a 3D vertex model, where the tissue geometry is represented by a set of vertices. The volume enclosed by triangulated surfaces joining the vertices corresponds to an epithelial cell. The cell apical surfaces, cell basal surfaces and cell-cell interfaces are subjected to different interfacial tensions, the edges joining vertices are subjected to line tensions, and a pressure constrains the total cell volume. These forces arise from the cytoskeleton and their relative magnitudes depend on the localisation of actin and myosin or other force-producing elements in the cell. We use the 3D vertex model as a tool to understand the mechanics of morphogenesis during development.

On larger length scales, we are developing a continuum theory for epithelial tissues, in order to establish a general framework for how tissues deform and flow on large spatial scales. Cell mechanics, cell rearrangements allowed by T1 transitions and cell division and apoptosis are taken into account to derive constitutive equations, describing how forces in the tissue depend on cell shape and other quantities characterising the state of the tissue.

Physics of active matter

We are interested in developing hydrodynamic theories of active matter. We are working on the mechanics of active surfaces, which are subjected to internal forces and torques. Active tensions tend to contract the surface area of the manifold, while active moments tend to locally bend the surface. We are interested in the surface shape changes and internal flows, which result from these active forces. We are also interested in nematic active fluids, and the chaotic patterns that emerge in these systems.

   

Guillaume Salbreux

guillaume.salbreux@crick.ac.uk
+44 (0)20 379 62009

  • Qualifications and history
  • 2008 PhD in Biological Physics, CNRS-Institut Curie, Paris, France
  • 2008 Postdoctoral Fellow, University of Michigan, USA
  • 2010 Postdoctoral Guest Scientist, Max Planck Institute for the Physics of Complex System, Dresden, Germany
  • 2011 Group Leader, Max Planck Institute for the Physics of Complex System, Dresden, Germany
  • 2015 Establishes lab at the Francis Crick Institute, London, UK