Random Walks Along Microtubules: The Stochastic dynamics of two molecular motors

Professor Charlie Peskin (NYU)

Microtubules are stiff protein polymers that form tracks inside biological cells along which material can be transported from one place to another both faster and with greater specificity than by diffusion through the cytoplasm. In this talk, we shall consider two molecular motors that run along these tracks. One of these is the motor protein kinesin, a two-headed molecule that literally walks along the microtuble towing its cargo (such as a membrane- bound vesicle) by means of a long elastic tether. The other motor involves the depolymerization of the microtubule itself, which can be used to drive the transport of structures that diffuse along the microtubule but cannot get off its depolymerizing end. We shall introduce mathematical models of these two motors and show how these models can be used to characterize the random walks that the motors generate. A synergistic and somewhat paradoxical interaction of both motors in chromosome transport during cell division will be proposed.