Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 63: Cytoskeletal filaments (Joint session BP, CPP)

CPP 63.9: Vortrag

Donnerstag, 19. März 2015, 12:15–12:30, H 1028

Contractile actin bundles without molecular motors — •Jörg Schnauß¹, Tom Golde¹, Carsten Schuldt¹, Sebastian Schmidt¹, Martin Glaser¹, Dan Strehle¹, Josef Käs¹, and Claus Heussinger² — ¹Institute for Experimental Physics I, University of Leipzig , Linnéstraße 5, 04103 Leipzig , Germany — ²Institute for Theoretical Physics, Georg-August University of Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany

Since the 1940, interactions of actin and its molecular motor myosin are known as the fundamental process for biological force generation. These interactions convert chemical energy into mechanical work by ATP hydrolysis. The dogma of molecular motors being the basis of all contractile forces has never been disproven. In this study we show an alternative force generation mechanism in the absence of molecular motors. The system is not driven by ATP hydrolysis and solely relies on minimization of free energy based on filament-filament interactions induced by a crowded environment. Dynamics of these contractions behave differently to a single filament pair shown in theoretical and experimental studies. We are able to show that the behavior of contractile actin bundles can be well described as an emergent phenomenon of multiple filament pairs. This crowding regime is well below the macromolecular content of cells and crowding effects have to be considered in cellular systems. We measured contraction velocities ranging from 0.10 to 0.65 µm/s and evaluated a force regime of 0.5 to 3.0 pN. Dynamics and forces of this non-dissipative process correspond to an active behavior of single myosin motors.