Condensed Matter Seminar

March 10 2016

G126 Noon

 

Hui-Shun Kuan

University of Colorado Boulder

 

Nonlinear dynamics and phase space flows to understand the phase behavior of motor protein motion on antiparallel filaments

 

Abstract

Motor protein motion on biopolymers can be described by driven diffusive models related to the totally asymmetric exclusion process (TASEP). Inspired by recent experiments on the motion of kinesin-4 motors on antiparallel microtubule overlaps, we develop a model incorporating the TASEP on two antiparallel lanes with binding kinetics and lane switching. We determine the steady-state motor density profiles and phase diagram using phase space flows at the mean-field level. We compared our results to kinetic Monte Carlo simulations. Phases previously identified for the single-filament model occur in the limit of zero switching rate. In addition, lane switching couples the density profiles on the two lanes and can lead to a new phase not possible for a single filament: switching moves motors from the higher density lane to lower density lane, causing local jamming and creating multiple domain walls. We determine the phase diagram of the model for both symmetric and general boundary conditions.