Active nematic order and dynamic lane formation of microtubules driven by membrane-bound diffusing motors ...

• Main Author: Hirst, Linda
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: FOS Physical sciences; Canada; Lanes; Orca
• Online Access: https://dx.doi.org/10.6071/m37088; https://datadryad.org/stash/dataset/doi:10.6071/M37088

Dynamic lane formation and long-range active nematic alignment is reported using a geometry in which kinesin motors are directly coupled to a lipid bilayer, allowing for in-plane motor diffusion during microtubule gliding. We use fluorescence microscopy to image protein distributions in and below the dense two-dimensional microtubule layer, revealing evidence of diffusion-enabled kinesin restructuring within the fluid membrane substrate as microtubules collectively glide above. We find that the lipid membrane acts to promote filament-filament alignment within the gliding layer, enhancing the formation of a globally aligned active nematic state. We also report the emergence of an intermediate, locally ordered state in which apolar dynamic lanes of nematically-aligned microtubules migrate across the substrate. To understand this emergent behavior, we implement a continuum model obtained from coarse graining a collection of self-propelled rods, with propulsion set by the local motor kinetics. Tuning the ... : The data includes 1) Measurements of microtubule length. 2) Calculations of order parameter in different phases. For experimental imaging we used fluorescence microscopy (Leica Microsystems Inc. DM 2500P fluorescence Microscope, (Buffalo Grove, IL, USA)) and confocal fluorescence microscopy (Zeiss LSM 889 with AiryScan + FAST and a Gallium arsenide phosphide (GaAsP) photon counting photodetector.). A QImaging Retigia Exi camera (Surrey, BC, Canada) and an ORCA - Flash4.0 LT+ Digital CMOS camera, (Hamamatsu, Shizuoka, Japan) were used to record fluorescence movies under low light conditions. The images were recorded at 10 second time intervals with either 20x, 40x, or 63x objectives. For the phase diagram in Figure 3a we used a region of interest (ROI) of 500px x 500px (where 2.1 px = 1 µm) and the following order parameter thresholds to determine the phase behavior: Nematic S > 0.25, Coexistence 0.20 < S < 0.25, Lane formation 0.10 < S < 0.20 and Isotropic 0 < S < 0.10. In Figure 3 (c-d) ...