Asymptotic Analysis of Microtubule-Based Transport by Multiple Identical Molecular Motors

TL;DR

This paper models microtubule-based transport by multiple molecular motors using stochastic differential equations, analyzing different regimes to predict motor behavior in vivo and with multiple motors attached.

Contribution

It introduces an asymptotic analysis framework for SDE models of molecular motor transport, bridging in vitro data with in vivo and multi-motor scenarios.

Findings

Classical experiments are in a different parameter regime than living cells.

Analytical predictions for highly viscous in vivo transport.

Predictions for dynamics with multiple motors attached.

Abstract

We describe a system of stochastic differential equations (SDEs) which model the interaction between processive molecular motors, such as kinesin and dynein, and the biomolecular cargo they tow as part of microtubule-based intracellular transport. We show that the classical experimental environment fits within a parameter regime which is qualitatively distinct from conditions one expects to find in living cells. Through an asymptotic analysis of our system of SDEs, we develop a means for applying in vitro observations of the nonlinear response by motors to forces induced on the attached cargo to make analytical predictions for two parameter regimes that have thus far eluded direct experimental observation: 1) highly viscous in vivo transport and 2) dynamics when multiple identical motors are attached to the cargo and microtubule.