A Semi-Analytical Model to Investigate Cargo Transport by Bi-Directional Molecular Motor Ensemble*

Deciphering mechanism of transportation of organelles by molecular motors is crucial to understand the genesis of neurodegenerative diseases. We model the ensemble behavior of motors using a semi-analytical approach. This approach uses an individual motor’s model to predict their ensemble behavior. The process of cargo transportation is modeled as Markov process with molecular motor arrangements being as its state which satisfies Markov property. Exact probabilities distribution functions of the relative configurations of motor is determined in order decipher the cargo transportation process.
When only unidirectional motors are carrying a cargo, this approach has revealed insights such as relative configurations approaching a unique steady state distribution, enforcing the robustness of the motor-cargo assembly. Also it has been observed that as the load on the cargo increases, motors tend to cluster together. We attempt to extend this analysis to ensembles with bidirectional motors such as both kinesin and dynein. This will aid to suggest new hypothesis about motor behavior and drive the design and realization of new experiments. Finally, we attempt to determine the factors responsible for deciding the “tug-of-war” vs coordinated movement.