Dresden 2014 – scientific programme

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BP: Fachverband Biologische Physik

BP 11: Posters: Cytoskeleton

BP 11.7: Poster

Tuesday, April 1, 2014, 09:30–12:30, P1

Impact of cell-sized confinement on the dynamics of actin polymerization — •Zoe Swank, Siddharth Deshpande, and Thomas Pfohl — University of Basel, Basel, Switzerland

Components of the cytoskeleton are generally geometrically confined in cells, thus the range of physical dynamics exhibited by polymers in response to external confinement is connected to our understanding of biological systems. Using a microfluidic platform, we have studied the effects of varying geometrical confinements on the semi-flexible biopolymer actin. We have designed microfluidic devices, containing separate micro-confinements of differing geometries, which may exchange macromolecules and ions with a connected inlet channel via diffusion. Hence, we are able to observe the polymerization of actin filaments in vitro within diffusion-controlled micro-confinements, subject to various geometrical parameters. Furthermore, it is possible to create a macromolecular concentration gradient across the micro-confinements, enabling the control of actin filament polarity during polymerization. Observations of single-filament and multiple-filament fluctuations are correlated, and the distribution of single filaments and filament networks are analyzed. Imposing a progressively narrower confinement has been shown to dampen polymer fluctuations and alter their distribution, while constraining filaments to increasing angles of external curvature is found to primarily affect the distribution of polymers within the confinement.