Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

BP: Fachverband Biologische Physik

BP 31: Posters: Biological Machines \& Motor Proteins

BP 31.2: Poster

Thursday, March 17, 2011, 17:15–20:00, P3

Tug-of-war of small ensembles of myosin II motors — •Philipp Albert, Thorsten Erdmann, and Ulrich S. Schwarz — Institute of Theoretical Physics, University of Heidelberg

Myosin II motors are non-processive and therefore have to work together in ensembles in order to generate appreciable levels of force. In the actin cytoskeleton of cells these ensembles are usually small and stochastic effects are therefore expected to be pronounced. The parallel cluster model (PCM) recently developed for small ensembles of myosin II motors takes advantage of the separation of time scales present in the myosin II hydrolysis cycle. The PCM reduces the complex network of stochastic transitions occurring in an ensemble consisting of several myosin II motors to a one-step master equation. We extend the PCM to a bipolar myosin II minifilament, resulting in a model for the stochastic tug-of-war between two non-processive motor ensembles. Stochastic simulations reveal that the movement of the bipolar minifilament can be described by a diffusive process, with a diffusion constant that depends on the size of the minifilament. In order to investigate mechanosensitivity of molecular motors, springs are added to the system as an external elastic element. For sufficiently large ensembles, increasing the stiffness results in a transition from a state with frequent detachment to an attached state.