This is the second Jacques Monod Conference focussing on the latest research on different types of cytoskeleton. Actin filaments and microtubules are the major cytoskeletal polymers in eukaryotic cells. As non-equilibrium polymers, they self-assemble and disassemble in a regulated and coordinated fashion and self-organise into dynamic higher order structures with complex functionalities in essential processes, such as cell polarisation, cell migration, cell division, and other morphogenetic processes important for cell differentiation. In bacteria, distantly related cytoskeletal proteins also coordinate cellular functions requiring the action of filaments. How complex functionalities emerge from the collective behaviour of the components of the cytoskeleton is a major open question in biology. Answering this important question will require the combined expertise from several disciplines. Several recent methodological developments in structural biology (cryo-EM, single particle analysis, tomography), biophysics (single molecule and super-resolution imaging) and cell biology (optogenetics and genome editing) have tremendously accelerated progress in several areas of actin and microtubule cytoskeleton research. At this conference, a multi-scale view of the cytoskeleton will be presented, including latest results on integrated actin/microtubule functions, cytoskeleton-membrane/boundary interactions and diversity of cytoskeletal arrangements between different cell types and cells in different species.
Benoit Vianay developed a new fast and large scale laser patterning technique of any binary pictures with a 100x obj precision by cutting and assembling large picture in small pieces. The video is real time.
This project was a joint effort with the artists of the Groupe LAPS. We used video-projection to overlay a cell's architecture onto a building's architecture to reveal their similarities and differences. Because of their microscopic size, cells are insensitive to gravity. Therefore, the laws that guide the assembly of the filaments supporting cell architecture are different from those laws that dictate the structure of a building. To compare these two types of architecture, the front facade of the hospital has been miniaturized to the size of a single cell, i.e. few hundredths of a millimetre. The dynamics of the miniature filaments within cells have been video-recorded over several days, and was shown as accelerated movies projected onto the building's facade. Thus, despite the tremendous differences in their spatial and temporal scales, two worlds came together for one night. The project was designed by Manuel Théry. Cells were micropatterned and movies were acquired on a Nikon confocal spinning disk by Andreas Christ. They were then arranged by Nadir Bouassria (LAPS) and Pierre Froment (LAPS), and sonorized by Erwan Quintin (LAPS). The final movie was projected onto the building by idscene.
We have organized the WORLD FIRST CELL RACE. The idea was to run against each others the fastest cells scientists are working with to study cell migration. To that end we microfabricate some thin tracks of extra-cellular matrix and to record cell migration on them. We organized the race with the help of 6 research teams throughout the world: the lab of Wendell Lim at UCSF, the lab of Tim Mitchison at HMS, the lab of Maddy Parsons at King College London, the lab of Holger Erfle at Bioquant (Heidelberg, Germany), the lab of Jean-Paul Thiery at Singapore, the lab of Matthieu Piel at the Institut Curie in Paris. Laboratories from all over the world have been invited to send us frozen cells. All types of modifications of genes expression were allowed as long as they were properly characterized. We received about 50 entrants from all organizing countries. Cells were thawed and plated on tracks microfabricated by the company CYTOO. They were then video-recorded for 24 hours. Paolo Maiuri (from Piel lab) developed an Image J macro to track single cell movement and measure several cell migration parameters, including cell speed of course. The fastest cells we recorded was a human embryonic mesenchymal stem cells running at 5.2 µm/min over more than 300 micrometers. All results were reported in a peer-reviewed publication in Current Biology (see Maiuri et al. Current Biology, 2012). We found an interesting universal correlation between cell speed and persistence during migration.