La recette des microtubules à l'actine. Cette vidéo, en français, a été tournée à l'occasion des 10 ans du prix Jeune Chercheur de la Société de Biologie Cellulaire de France, attribué à Manuel Théry en 2010. Elle illustre comment en améliorant jour après jour la composition du mélange biochimique, les membres de l'équipe ont réussi à mettre au point une méthode pour faire pousser ensemble des microtubules et des filaments d'actine.
This movie was made for the annual meeting of the ASCB and EMBO #cellbio2020 It shows how young students and experienced scientists work together to address fundamental questions in cell biology. It illustrates the process of research: the initial question, the experiments, the multiple errors and failures, and the never-ending quest for the truth behind the magic. The stochastic switching between microtubule growth and shrinkage is a fascinating and unique process in the regulation of the cytoskeleton. To understand it, almost all attention has been focused on the microtubule ends. However, recent experiments on reconstituted microtubule in vitro have revealed that tubulin dimers can also be exchanged in protofilaments along the microtubule shaft, thus repairing the microtubule and protecting it from disassembly. In this presentation we will discuss the role of microtubule self-repair in cells and provide novel evidence that it confers unexpected mechano-sensitive properties to the microtubule network. We applied controled deformations to living cells and found that compressive forces can stabilise microtubules. This process allows the microtubule network to sense and adapt its architecture to the force field cells are submitted to, a process that has long believed to be the apanage of the actin network.
« Cells architecture dynamics allows them to adapt to their environment.Within organ they conform to the organ. On a building they conform to the building. »
This project stems from the collaboration between the biologist of the CEA/CNRS and the plasticians from the groupe LAPS. It is based on the use of microfabrication, cell culture, biochemistry, microscopy and video-projection to show living architectures adapting to the architecture of a building.
Cells have a skeleton, the cytoskeleton, made of several networks of filaments. The growth of filaments and contraction of these networks power shape changes and cell motion. But the rules directing these assemblies can?t be revealed in the high complexity of intra-cellular space. They must be studied in simpler and more controled conditions. To that end, scientist break cells into pieces, purify filament components and study their self-organization in cell-free conditions.
The facade of the Interdisciplinary Research Center has been miniaturised to the size of a single cell, ie few hundredths of a millimeter. Cell moves and the growth of isolated cytoskeleton filaments on this structure have been video-recorded on a microscope. Eventually, the movies will be projected onto the original building. Thus, despite the tremendous difference in their spatial and temporal scales, these two worlds will come together for one night.
Conception : CytoMorpho Lab, Groupe LAPS
Réalisation : Benoit Vianay, Christophe Guerin, Jérémie Gaillard, Matthieu Gélin, Thomas Bessy, Chiara de Pascalis, Benoit Souquet, Andreas Christ, Pablo Saez and Manuel Théry pour le CytoMorpho Lab. Nadir Bouassria, Pierre Froment et Erwan Quintin pour le groupe LAPS.
Increasing numbers of researchers are turning cell biology upside down, and attempting to reconstitute complex cellular processes and structures in vitro by isolating their elementary components. While not easy, the rewards of bottom-up approaches are high, as defining the minimal set of components for any process or structure can provide tremendous molecular and mechanistic insights into the cell and how it works. The use of technologies, such as micro-patterning and microfluidics, is also enabling reconstitution assays to become more sophisticated and elaborate, allowing researchers to tackle more complex biological processes across a range of scales.
We invite you to showcase your breakthrough research on all aspects of reconstituting cell biology in this special issue. We are particularly interested in the reconstitution of intracellular processes such as RNA synthesis and export, cytoskeleton self-organization, and membrane folding and sorting, as well as processes involving cell biology such as the regulation of stem cell differentiation, immune cell activation and cell migration, as long as the experimental strategy is based on the development of specific methodology or tools aiming at deconstructing a complex process into simple components, and at reproducing the core mechanism on which it is based.
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.