Motor-driven microtubule diffusion in a photobleached dynamical coordinate system

Area of Science:

• Physics
• Biophysics
• Materials Science

Background:

• Active matter systems demonstrate emergent organization from individual components.
• Internal dynamics within the bulk of active matter networks remain poorly understood.

Purpose of the Study:

• To investigate the internal redistribution and deformation within a contracting microtubule network.
• To quantify the interplay between advection and diffusion in active matter systems.

Main Methods:

• Utilized light-dimerizable kinesin motors to control microtubule network formation and contraction.
• Employed photobleaching to create a dynamic coordinate system for observing network deformation.
• Measured the effective diffusion constant and diffusive timescale within the bulk network.

Main Results:

• Network contraction rate is dictated by motor speed.
• Observed diffusive-like redistribution within the bulk, with an effective diffusion constant two orders of magnitude lower than free diffusion.
• Diffusive timescale is only a factor of ≈3 slower than advection on micron scales.

Conclusions:

• Both global contraction and long-time relaxation are motor-driven processes.
• Local competition exists within the network bulk, influencing diffusive behavior.
• The study provides insights into the complex internal dynamics of active matter networks.