Modelling Cargo Transport and Deformation by Molecular Motors along Cytoskeletal Filaments

In this thesis, we present a study of cargo transport or behaviors in a cell by
clusters of molecular motors on a single and many parallel or anti-parallel mi-
crotubules. Molecular motors can be processive motors or non-processive motors
which can bind on and o� and switch between microtubules (lanes). Our study in-
cludes analytical theory, simulations and a detailed comparison with experiments.
We extend the analytic expressions for the non-processive motors to the case of
�nite binding sites on a single lane and multiple lanes, as presented in chapter of
one-lane and many-lane model, respectively. We performed Monte Carlo latticed
based stochastic simulations to validate the corresponding system. The simula-
tions also include simple exclusion process and sequence preservation of motors.
Our results show that the limiting number of binding sites along the lanes and se-
quence preservation reduce the probability of non-processive motors binding, but
has a relatively small e�ect on the velocity. Multiple-lane transport can enhance
the velocity and averaged run length and reduce the delivery time. We also study
cargo behaviour using a tug-of-war model in which the lanes on which motors step
are oriented in anti-parallel arrays between right and left ends of the cargo, as pre-
sented in chapter of cargo deformation. This mechanism generates motor pulling
force onto the cargo which results in changing its shape and position. The cargo
can be any cargoes acting as a spring and the nucleus is the example of cargo that
we are interested in. This model provides new insights of nuclear deformation and
displacement caused by the motor pulling force. Our simulations show that the
deformation and displacement can be induced by the increasing number of mi-
crotubules. This corresponds with the experimental results of Susana Godinho's
group.