  Pattern formation and the mechanics of a mixture of actin filaments and
myosin motors that is confined by a rigid membrane is investigated. By using a
coarse-grained molecular dynamics model, we demonstrate that the competition
between the depletion force and the active force of the motors gives rise to
actin accumulation in the membrane vicinity. The resulting actomyosin structure
exerts pressure on the membrane, that, due to nematic alignment of the
filaments, converges to a constant for large motor active force. The results
are independent of filament length and membrane curvature, indicating the
universality of this phenomenon. Thus, this study proposes a novel mechanism by
which the compounds of the cytoskeleton can self-organize into a higher-order
structure.
