Microtubules organisation within a biological cell using mean field theory #

Tamsin A Spelman, Cameron Gibson, Henrik Jonsson

Poster session

Abstract #

All Eukaryotic cells have an active fibre network called the cytoskeleton consisting of larger microtubule fibres and smaller actin fibres (and in animals intermediate filaments too). These fibres are essential for cell functions such as structural support and organelle transport. The microtubule network is active with fibres continually in a state of growth or shrinkage, which they can change between. New fibres start growing in a process called nucleation and microtubules will change direction or their state if they collide. These interactions allow the microtubule network to be anisotropic, as is observed experimentally.

A mean field theory (MFT) mathematical model was previously developed to study microtubule organisation when microtubules are restricted to 2D [1]. Here we extend the mathematical MFT model to 3D and compare the results to a 3D computational model which models all microtubules individually. We classify our results in terms of a control parameter which encapsulates the microtubule properties such as growth rate. Using 3D MFT, we identify the value of this control parameter where the microtubule system can change from an isotropic to anisotropic system, which we compare to simulations for an increasing value of this control parameter. We then consider the effect of two known microtubule behaviours: zippering and severing. Finally, we compare with experimental measurements of microtubule properties from the literature.

[1] R. J. Hawkins, S. H. Tindemans, and B. M. Mulder. Model for the orientational ordering of the plant microtubule cortical array. Phys. Rev. E, 82:011911, 2010.