Microtubules (MTs) are central to the organisation of the eukaryotic
intracellular space and are involved in the control of cell morphology. For these purposes, MT
polymerisation dynamics are tightly regulated. Using automated image analysis software, we investigate the
spatial dependence of MT dynamics in
interphase fission yeast cells with unprecedented
statistical accuracy. We find that MT catastrophe
frequencies (switches from
polymerisation to depolymerisation) strongly depend on
intracellular position. We provide evidence that compressive forces generated by MTs growing against the cell pole locally reduce MT growth velocities and enhance catastrophe
frequencies. Furthermore, we find evidence for an MT length-dependent increase in the catastrophe
frequency that is mediated by kinesin-8 proteins (Klp5/6). Given the intrinsic susceptibility of MT dynamics to compressive forces and the widespread importance of kinesin-8 proteins, we propose that similar spatial regulation of MT dynamics plays a role in other cell types as well. In addition, our systematic and
quantitative data should provide valuable input for (mathematical) models of MT organisation in
living cells.
