le 26 mars 2015 à 10 h 30
Olivier Thoumine Institut Interdisciplinaire de Neuroscience, Université de Bordeaux

To trigger cell motility, forces generated by the cytoskeleton must be transmitted physically to the external environment through transmembrane adhesion molecules. One model put forward twenty years ago to describe this process is the molecular clutch by which a modular interface of adaptor proteins mediates a dynamic mechanical connection between the actin flow and cell adhesion complexes. Recent optical imaging experiments have identified key clutch molecules linked to specific chemical and mechanical signal transduction pathways, particularly regarding integrins in migrating cells, IgCAMs in neuronal growth cones, and cadherins at intercellular junctions (Giannone et al., Trends Cell Biol 2009).

In this talk, I will show examples of clutch-like mechanisms between the actin flow and N-cadherin adhesions in neuronal motile structures. Two structures will be considered: i) growth cones migrating on N-cadherin coated substrates, and ii) dendritic filopodia making cadherin-dependent contacts with axons. In both cases, engagement of cadherin adhesions slow down the actin flow, allowing migration and/or enlargement of the structure. I will show live imaging data (Single Molecule Tracking, Fluorescence Recovery After Photobeaching) on actin, α-catenin, and N-cadherin molecules fused to fluorescent proteins and expressed in neurons. I will present ways to quantify protein diffusion, flow, and turnover, as well as computer simulations to interpret the data (Chazeau et al., Mol Biol Cell, 2015; Garcia et al., in revision).

Lieu(x) :         Amphithéatre Pierre Curie, Ecole Polytechnique

Contact :       Antigoni Alexandrou
                      antigoni.alexandrou at polytechnique.edu

À télécharger :       Séminaire THOUMINE.pdf - PDF