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Laurent Blanchoin - Directed actin self assembly and contractility

Speaker : Laurent Blanchoin - Laboratoire de Physiologie Cellulaire Végétale - CNRS/iRTSV - CEA Grenoble

When : thursday 04th April at 11 am

Where : Salle CO23 (grande salle de réunions du CBP rez-de-chaussée LR6)

Title : Directed actin self assembly and contractility

The organization of actin filaments into higher-ordered structures governs eukaryotic cell shape and movement. Global actin network size and architecture is maintained in a dynamic steady-state through regulated assembly and disassembly. We have developed a micropatterning method that enables the spatial control of actin nucleation sites for in vitro assays. These actin templates were used to evaluate the response of oriented actin structures to myosin-induced contractility. We determine that myosins selectively contract and disassemble anti-parallel actin structures while parallel actin bundles remain unaffected. In addition, the local distribution of nucleation sites and the resulting orientation of actin filaments regulate the scalability of the contraction process (Fig1). This “orientation selection” mechanism for selective contraction and disassembly reveals how the dynamics of the cellular actin cytoskeleton is spatially controlled by actomyosin contractility. Further application of the micropatterning method will be presented in particular recent data on the reconstitution of a lamellipodium-type of actin organization. < !—[if !vml]—>

Fig. 1 : – Image reconstruction of time series of myosin-induced contraction of actin networks nucleated from a dotted ring (red actin filament), (green myosin). Scale bar : 5 µm

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