Centre Interdisciplinaire de Recherche en Biologie, Collège de France, Paris

Friday, Nov the 18th at 11 AM in Amphi Sauvy

How actin dynamics rules filopodia retraction to probe the environment

Filopodia are functional units described as finger-like membrane extensions acting as sensor organelles to probe the environment and initiate contacts, transmit signals or guide cell migration. How cells integrate external signal to reorganize the actin cytoskeleton is crucial for the sensing function of filopodia. FRAP experiments in spinning disk confocal microscopy reveals that the control of filopodia dynamics is ruled by the regulation of actin polymerization. Force measurements using optical tweezers unravels that adhesion at filopodia tips conditions filopodia retraction. We propose a model where actin polymerization from the base of filopodia drives their retraction, and that retraction forces are set by the strength of adhesion of substrates at filopodia tips.

References : 

• Bornschlögl T, Romero S, Vestergaard CL, Joanny JF, Van Nhieu GT, Bassereau P. 2013. Filopodial retraction force is generated by cortical actin dynamics and controlled by reversible tethering at the tip. Proc Natl Acad Sci U S A. 110:18928-33.
• Romero S, Quatela A, Bornschlögl T, Guadagnini S, Bassereau P, Tran Van Nhieu G. 2012. Filopodium retraction is controlled by adhesion to its tip. J Cell Sci. 125(:4999-5004.
• Romero S, Grompone G, Carayol N, Mounier J, Guadagnini S, Prevost MC, Sansonetti PJ, Van Nhieu GT. 2011. ATP-mediated Erk1/2 activation stimulates bacterial capture by filopodia, which precedes Shigella invasion of epithelial cells. Cell Host Microbe 9:508-19.