Eur. Phys. J. E (2005) 18: 41-54
https://doi.org/10.1140/epje/i2005-10029-3

Original Article

Nonlinear competition between asters and stripes in filament-motor systems

¹ Theoretische Physik, Universität des Saarlandes, D-66041, Saarbrücken, Germany
² Theoretische Physik, Universität Bayreuth, D-95440, Bayreuth, Germany

^* e-mail: walter.zimmermann@uni-bayreuth.de

Received: 17 January 2005
Accepted: 16 July 2005
Published online: 7 October 2005

Abstract

A model for polar filaments interacting via molecular motor complexes is investigated which exhibits bifurcations to spatial patterns. It is shown that the homogeneous distribution of filaments, such as actin or microtubules, may become either unstable with respect to an orientational instability of a finite wave number or with respect to modulations of the filament density, where long-wavelength modes are amplified as well. Above threshold nonlinear interactions select either stripe patterns or periodic asters. The existence and stability ranges of each pattern close to threshold are predicted in terms of a weakly nonlinear perturbation analysis, which is confirmed by numerical simulations of the basic model equations. The two relevant parameters determining the bifurcation scenario of the model can be related to the concentrations of the active molecular motors and of the filaments, respectively, which both could be easily regulated by the cell.