Self-organized patterns of microtubules and molecular motors
 	
JF Joanny, S. Pattanayak, A. Sciortino, L. Blanchoin and M. Théry

The internal organization of cells is largely determined by the architecture and orientation
of the microtubule network. Microtubules serve as polar tracks for the selective transport
of specific molecular motors toward either their plus or minus ends. 

We present  experiments on reconstituted systems and theory to study
the interaction of microtubules with both plus-­and minus-­end directed motors bound to a
fluid membrane. Depending on motor concentrations, the system leads either to the
constant transport of microtubules or to their alignment, stacking, and immobilization in
regular bands that separate motors into domains of opposite polarities. 

In bands, microtubules all share the same polarity and segregate the two opposing motors.
The regular patterns result from the balance of forces produced by the two motors
as they walk in opposite directions along each microtubule.

The microtubule patterns result from  active microphase separation where the micotubules can be considered as
active surfactants pumping the motors on on each side depending on their polarity. We present a model for the
steady state patterns in one and two dimensions and an active Cahn Hilliard theory, wich describes the kinetics of the phase separation.