In this paper, we introduce an ASEP-like transport model for bidirectional motion of particles on a multi-lane lattice. The model is motivated by {\em  experiments URLanelle motility along a microtubule (MT),  where particles are propelled by molecular motors (dynein and kinesin) along the thirteen protofilaments of the MT . In the model, particles can switch directions of motion due to "tug-of-war" events between counteracting motors. Collisions of particles on the same lane can be cleared by switching to adjacent filaments (lane changes). We analyze transport properties of the model with no-flux boundary conditions at the end of a MT ("plus-end" or tip).  In particular, we find a nonlinear scaling of the mean {\em   number of particles accumulated at the tip (%DIFDELCMD < {\em %%% tip size ) with injection rate and an associated phase transition leading to {\em pulsing states} characterized by periodic filling and emptying of the system . Moreover, we show that the ability of changing protofilaments can affect the transport efficiency. Finally, we show that the particle-direction change rate obtained from experiments is close to optimal in order to achieve efficient motor URLanelle transport in a living cell .
In this paper, we introduce an ASEP-like transport model for bidirectional motion of particles on a multi-lane lattice. The model is motivated by {\em in vivo experiments URLanelle motility along a microtubule (MT), consisting of thirteen protofilaments, where particles are propelled by molecular motors (dynein and kinesin) . In the URLanelles (particles) can switch directions of motion due to "tug-of-war" events between counteracting motors. Collisions of particles on the same lane can be cleared by switching to adjacent protofilaments (lane changes). We analyze transport properties of the model with no-flux boundary conditions at one end of a MT ("plus-end" or tip). We show that the ability of lane changes can affect the transport efficiency and the particle-direction change rate obtained from experiments is close to optimal in order to achieve efficient motor URLanelle transport in a living cell. In particular, we find a nonlinear scaling of the mean {\em tip size (the number of particles accumulated at the tip %DIFDELCMD < {\em %%% ) with injection rate and an associated phase transition leading to {\em pulsing states} characterized by periodic filling and emptying of the system .
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in vivo
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consisting of thirteen protofilaments,
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along the thirteen protofilaments of the MT
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model, particles
URLanelles (particles)
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filaments
protofilaments
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the
one
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We show that the ability of lane changes can affect the transport efficiency and the particle-direction change rate obtained from experiments is close to optimal in order to achieve efficient motor URLanelle transport in a living cell.
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tip size
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(the
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tip size
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. Moreover, we show that the ability of changing protofilaments can affect the transport efficiency. Finally, we show that the particle-direction change rate obtained from experiments is close to optimal in order to achieve efficient motor URLanelle transport in a living cell