Directed actin cytoskeleton self organization

Laurent Blanchoin (CNRS & CEA Grenoble)

The actin cytoskeleton is a key component of the cellular architecture that governs eukaryotic cell shape and movement. However, understanding actin organization and dynamics in vivo is a complex challenge. To reconstitute in vitro the diversity of cellular actin organizations, we have developed a micropatterning method that enables the spatial control of actin nucleation sites (Reymann et al., Nat. Mat., 2010). These actin templates were used to reconstitute a lamellipodium-type of actin organization and evaluate how actin assembly controls speed and steering during actin-based motility. Our results allowed us to evaluate the growth rate as a function of three factors, the mechanical load, the local actin monomer concentration, and the geometrical organization of actin filament. Our results can explain how the cell can regulate the rate of protrusion locally by varying both density and architecture of the actin network. Further application of the micropatterning method will be presented in particular recent data on the fabrication of three-dimensional electrical connections by means of directed actin self-organization (Galland et al., Nat. Mat., 2013).