Microtubules produce mechanical forces as they grow and shrink. They also support the forces
produced by molecular motors. The spatial distribution of these two sets of forces orients intra-cellular transport, positions organelles, and thereby determines the cellular compartmentation and polarity.
The architecture of microtubule network depends on two main contributions: the templated
growth, which is defined by the amount and localization of microtubule nucleators, and the selforganization of microtubule and motors, which depends on the concentration of various motors and the number and length of microtubules. This contribution has been much studied in the spindle formed by microtubules during mitosis, but is relatively uncharacterized in interphase although it is central to most cell functions.
We recently managed to define some working conditions allowing us to turn down the
templated growth and highlight the self-organization of microtubule and motors. To our surprise, we found that components could self-pattern themselves into multiple domains, containing either plus-end or minus-end directed motors, separated by bundles of aligned microtubules.
We propose to further explore these conditions and define the phase diagram defining the
number and shape of these domains. This first part will serve as a basis to define a deeper study of this process in various cell types and their evolution as cells progress from a proliferating to a differentiated state (ie as the self-organization progressively replaces the templated growth).