Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

4-POS Board 2 Rotation, Twisting and Pulling: The Rich Dynamics of Filopodia Natascha Leijnse, Lene B. Oddershede, Poul M. Bendix . University of Copenhagen, Copenhagen, Denmark.

Filopodia allow the cell to sense and interact with their surroundings. Rigidity sensing and application of piconewton traction forces are key functions that filopodia employ to sense and regulate cellular interactions. However, despite their ubiquitous presence in most cells, their different modes of movement remains poorly characterized. Recently, we found surprising evidence for a new pulling mechanism originating from twisting of the actin within the filopodium [1,2]. This mechanism can only be present in filopodia which contain a rotating actin bundle. By imaging the actin, we clearly observed rotation and retrograde flow of small buckles which formed in filopodia from HEK293 cells. The movement of these buckles was found to be coupled to the pulling force exerted by the filopodium in a manner which indicated that torsional twist was accumulated in the actin bundle. Our results provide the first clear evidence of rotation of the actin within filopodia a key property which might facilitate both interaction and exploration of the cell’s 3D environment. 1. Leijnse N, Oddershede LB, Bendix PM. An updated look at actin within filopodia. A Review, Cytoskeleton 2015, 72, 71-79. 2. Leijnse N, Oddershede LB, & Bendix PM. Helical buckling of actin inside filopodia generates traction. PNAS 2015, 112(1), 136-141.

100