Mechanical Regulation of Neurite Polarization and  Growth: A Computational Study.

Mechanical Regulation of Neurite Polarization and Growth: A Computational Study.
Biophys J. 2020 Mar 14;:
Authors: Jakobs MAH, Franze K, Zemel A
Abstract
The densely packed microtubule (MT) array found in neuronal cell projections (neurites) serves two fundamental functions simultaneously: it provides a mechanically stable track for molecular motor-based transport and produces forces that drive neurite growth. The local pattern of MT polarity along the neurite shaft has been found to differ between axons and dendrites. In axons, the neurons' dominating long projections, roughly 90% of the MTs orient with their rapidly growing plus end away from the cell body, whereas in vertebrate dendrites, their orientations are locally mixed. Molecular motors are known to be responsible for cytoskeletal ordering and force generation, but their collective function in the dense MT cytoskeleton of neurites remains elusive. We here hypothesized that both the polarity pattern of MTs along the neurite shaft and the shaft's global extension are simultaneously driven by molecular motor forces and should thus be regulated by the mechanical load acting on the MT array as a whole. To investigate this, we simulated cylindrical bundles of MTs that are cross-linked and powered by molecular motors by iteratively solving a set of force-balance equations. The bundles were subjected to a fixed load arising from actively generated tension in the actomyosin cortex e...

Source: Biophysical Journal - March 13, 2020 Category: Physics Authors: Jakobs MAH, Franze K, Zemel A Tags: Biophys J Source Type: research