Microtubule Dynamics: Experimental Evidence and Numerical Modelling

Abstract

The involvement of GTP hydrolysis in microtubule assembly introduces a number of characteristic observable properties in the steady-state system, namely a time-dependent length redistribution process, a high level of steady-state GTP hydrolysis, unusually fast tubulin exchange kinetics, and, most significantly, the coexistence of interconverting growing and shrinking microtubules within the population. We evaluate and model the implications of these dynamic properties and we present a “Lateral Cap” model in which co-operative interactions in the microtubule end account for observed dynamic properties under both steady-state and extreme non-steady state conditions. We examine the ways in which factors such as metal ions, drugs, and microtubule associated proteins can exert different degrees of control of the behaviour of dynamic microtubule populations appropriate for regulation of their biological function.