  Intracellular cargos which are transported by molecular motors move
stochastically along cytoskeleton filaments. In particular for bidirectionally
transported cargos it is an open question whether the characteristics of their
motion can result from pure stochastic fluctuations or whether some
coordination of the motors is needed. The results of a mean-field model of
cargo-motors dynamics, which was proposed by M\"uller et al.[1] suggest the
existence of high motility states which would result from a stochastic
tug-of-war. Here we analyze a non-mean field extension of their model, that
takes explicitly the position of each motor into account. We find that high
motility states then disappear. We consider also a mutual motor-motor
activation, as an explicit mechanism of motor coordination. We show that the
results of the mean-field model are recovered only in case of a strong
motor-motor activation in the limit of a high number of motors.
