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Séminaire impromptu - Stéphane VassilopoulosMetal-replica EM in the 21st century

Abstract :

 In cell biology, particular importance is given to developing new methods of sample preparation that will achieve a more natural appearance of samples in the microscope
. To accomplish this, scientists have developed the metal-replica electron microscopy (EM) technique directly on unroofed cultured cells. This particular EM technique permits visualization of the inner side of cell membranes and their components. Metal-replicas have profoundly shaped our understanding of the functional morphology of the cell and used to capture several different cellular processes including remodeling of cytoskeletons, membrane trafficking, cell-to-cell contacts and formation of extracellular matrices. Combined to transmission electron microscopy (TEM), it is an invaluable method to reveal the composition of the PM and to directly observe macromolecular complexes including the cytoskeleton and endocytic membrane invaginations at high resolution. Here, I will outline the history of this particular EM technique and describe different methodologies and some key applications in cell biology including visualization of the cytoskeleton and different endocytic structures such as clathrin coated pits and caveolae.

Selected publications

Franck, A., Laine, J., Moulay, G., Trichet, M., Gentil, C., Fongy, A., Bigot, A., Benkhelifa-Ziyyat, S., Lacene, E., Thao Bui, M., et al. (2018). Clathrin plaques form mechanotransducing platforms. bioRxiv.

Randrianarison-Huetz, V., Papaefthymiou, A., Herledan, G., Noviello, C., Faradova, U., Collard, L., Pincini, A., Schol, E., Decaux, J.F., Maire, P., et al. (2018). Srf controls satellite cell fusion through the maintenance of actin architecture. J. Cell Biol. 217, 685–700.

Elkhatib, N., Bresteau, E., Baschieri, F., Rioja, A.L., van Niel, G., Vassilopoulos, S., and Montagnac, G. (2017). Tubular clathrin/AP-2 lattices pinch collagen fibers to support 3D cell migration. Science 356.

Lamaze, C., Tardif, N., Dewulf, M., Vassilopoulos, S., and Blouin, C.M. (2017). The caveolae dress code: structure and signaling. Curr. Opin. Cell Biol. 47, 117–125.

Vassilopoulos, S., Gentil, C., Lainé, J., Buclez, P.-O., Franck, A., Ferry, A., Précigout, G., Roth, R., Heuser, J.E., Brodsky, F.M., et al. (2014). Actin scaffolding by clathrin heavy chain is required for skeletal muscle sarcomere organization. J. Cell Biol. 205, 377–393.