Events

SEMS seminars: Prof Guillaume Charras, UCL

Centre for Bioengineering 
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Date: 19 February 2025   Time: 15:00 - 16:00    Add this event to your calendar 

Location: SEMS Seminar Room, 3rd floor, EngineeringĀ Building

Title:

Control of morphogenesis by the actin cortex in single cells and multicellular aggregates

Abstract:

The actin cortex is a thin meshwork of actin filaments, myosin motors and actin-binding proteins that lies below the membrane. Mechanical changes in the cortex play an essential role in morphogenesis of cells and tissues. I will present work examining the role of the cortex in cell division and the shape of multicellular aggregates.

As they enter mitosis, cells undergo profound shape changes that are controlled by gradients in mechanical tension arising in the submembranous actin cortex. These changes are controlled by RhoGTPases, key regulators of the cytoskeleton and contractility. In turn, RhoGTPase activity is regulated by RhoGEFs that activate them and RhoGAPs that inactivate them. Despite their central role in cell morphogenesis, we know little about how RhoGEFs control the changes in cell mechanics that drive shape change. I will present work examining the link between signalling and cell mechanics using AFM, imaging, and optogenetics.

During embryonic morphogenesis, tissue shape arises from interactions between cells. In tissues, the spatial patterning of cellular surface stresses generated by myosins interplays with intercellular adhesions to yield complex shapes. I will present recent work examining how tension in the cell cortex and across intercellular contacts shapes small aggregates of cells, such as the early C Elegans embryo.

About the speaker

After an undergraduate degree in Physics and Engineering in Paris, Prof Charras became fascinated by Cell Biology and turned my research interests to Biophysics. Prof Charras was fortunate to be exposed to many facets of Bioengineering and Biophysics through Masters degree at the Georgia Institute of Technology in Atlanta and through PhD work at UCL. During this time, Prof. Charras worked in the general area of cell mechanics using experimental techniques such as AFM and electrophysiology as well as computational simulation techniques, all of which remain key to lab's present research.

Prof Charras then decided to do a post-doc in a Cell Biology lab to acquire training in molecular cell biology techniques in Harvard Medical school. There, Prof. Charras was fortunate to be exposed to the fearless experimentators of the Mitchison lab, first in the department of Cell Biology and then in the department of Systems Biology. During this time, Prof. Charras worked primarily on blebbing and the cell cortex, at the time a rather obscure topic. This still forms one of the research directions in laboratory and has many connections to other parts of the lab's research. While in Boston, a chance encounter with microfluidics led to start working on cell migration in confined environments in collaboration with Daniel Irimia at MGH.

Since establishing laboratory at the London Centre for Nanotechnology, research has generally focused on cell and tissue mechanics with a focus on the cytoskeleton. However, Prof. Charras curious about many aspects of Cell and Developmental Biology and often venture into other areas than main focus. Prof Charras lab's research borrows concepts and tools from Physics and Engineering to answer fundamental questions in Cell and Developmental Biology.

https://profiles.ucl.ac.uk/10135-guillaume-charras/about

Updated by: Zion Tse