Actively crosslinked microtubule networks: mechanics, dynamics and filament sliding
arXiv:1812.01079 · doi:10.1038/s41567-019-0642-1
Abstract
Cytoskeletal networks are foundational examples of active matter and central to self-organized structures in the cell. In vivo, these networks are active and heavily crosslinked. Relating their large-scale dynamics to properties of their constituents remains an unsolved problem. Here we study an in vitro system made from microtubules and XCTK2 kinesin motors, which forms an aligned and active gel. Using photobleaching we demonstrate that the gel's aligned microtubules, driven by motors, continually slide past each other at a speed independent of the local polarity. This phenomenon is also observed, and remains unexplained, in spindles. We derive a general framework for coarse graining microtubule gels crosslinked by molecular motors from microscopic considerations. Using the microtubule-microtubule coupling, and force-velocity relationship for kinesin, this theory naturally explains the experimental results: motors generate an active strain-rate in regions of changing polarity, which allows microtubules of opposite polarities to slide past each other without stressing the material.
References in corpus (11)
- Modeling semiflexible polymer networks
- Generic theory of active polar gels: a paradigm for cytoskeletal dynamics
- Velocity Correlations in an Active Nematic
- Pattern formation of microtubules and motors: inelastic interaction of polar rods
- Actively Contracting Bundles of Polar Filaments
- Fiber networks amplify active stress
- Multiscale polar theory of microtubule and motor-protein assemblies
- Bridging the microscopic and the hydrodynamic in active filament solutions
- Hydrodynamic length-scale selection and effective viscosity in microswimmer suspensions
- Connecting macroscopic dynamics with microscopic properties in active microtubule network contraction
- Kinetic theory of pattern formation in mixtures of microtubules and molecular motors
Cited by in corpus (12)
- Multiscale Microtubule Dynamics in Active Nematics
- Towards the cellular-scale simulation of motor-driven cytoskeletal assemblies
- A design framework for actively crosslinked filament networks
- Active restructuring of cytoskeleton composites leads to increased mechanical stiffness, memory, and heterogeneity
- Active liquid crystals powered by force-sensing DNA-motor clusters
- How crosslink numbers shape the large-scale physics of cytoskeletal materials
- Self-organization and shape change by active polarization in nematic droplets
- Hyperphosphorylation-Induced Phase Transition in Vesicle Delivery Dynamics of Motor Proteins in Neuronal Cells
- Length Regulation Drives Self-Organization in Filament-Motor Mixtures
- Memory effects, arches and polar defect ordering at the cross-over from wet to dry active nematics
- Programming Boundary Deformation Patterns in Active Networks
- Filamentous Active Matter: Band Formation, Bending, Buckling, and Defects