Multiscale modeling and simulation of microtubule–motor-protein assemblies
Year: 2015
Type: article
Abstract: Microtubules and motor proteins self-organize into biologically important assemblies including the mitotic spindle and the centrosomal microtubule array. Outside of cells, microtubule-motor mixtures can form novel active liquid-crystalline materials driven out of equilibrium by adenosine triphosphate-consuming motor proteins. Microscopic motor activity causes polarity-dependent interactions between motor proteins and microtubules, but how these interactions yield larger-scale dynamical behavior such as complex flows and defect dynamics is not well understood. We develop a multiscale theory for microtubule-motor systems in which Brownian dynamics simulations of polar microtubules driven by motors are used to study microscopic organization and stresses created by motor-mediated microtubule interactions. We identify polarity-sorting and crosslink tether relaxation as two polar-specific sources of active destabilizing stress. We then develop a continuum Doi-Onsager model that captures polarity sorting and the hydrodynamic flows generated by these polar-specific active stresses. In simulations of active nematic flows on immersed surfaces, the active stresses drive turbulent flow dynamics and continuous generation and annihilation of disclination defects. The dynamics follow from two instabilities, and accounting for the immersed nature of the experiment yields unambiguous characteristic length and time scales. When turning off the hydrodynamics in the Doi-Onsager model, we capture formation of polar lanes as observed in the Brownian dynamics simulation.
Source: Physical Review E
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: green
Awards: CAREER: Molecular Motors and Protein Motion: From Mechanisms to Collective Effects, Soft Materials Research Center, Understanding mitotic spindle positioning by integrated modeling and experiment, Interdisciplinary Predoctoral Training in Molecular Biophysics, NYU MRSEC: Semantophoretic Assemblies, Collaborative Research: Hydrodynamic Theories of the Dynamics, Fluctuations, Boundaries, and Shapes of Flocks, MRI-Consortium: Acquisition of a Supercomputer by the Front Range Computing Consortium, Collaborative Research: The Analysis and Simulation of Biologically Active Suspensions, APPLIED ANALYSIS AND COMPUTATIONAL MATHEMATICS
OpenAlex ID: W2209140502