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arXiv · 0812.3908

Microtubule depolymerization by the kinesin-8 motor Kip3p: a mathematical model

L. E. Hough·Anne Schwabe·Matthew A. Glaser·J. Richard McIntosh·M. D. Betterton
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Abstract

Proteins from the kinesin-8 family promote microtubule (MT) depolymerization, a process thought to be important for the control of microtubule length in living cells. In addition to this MT shortening activity, kinesin 8s are motors that show plus-end directed motility on MTs. Here we describe a simple model that incorporates directional motion and destabilization of the MT plus end by kinesin 8. Our model quantitatively reproduces the key features of length-vs-time traces for stabilized MTs in the presence of purified kinesin 8, including length-dependent depolymerization. Comparison of model predictions with experiments suggests that kinesin 8 depolymerizes processively, i.e., one motor can remove multiple tubulin dimers from a stabilized MT. Fluctuations in MT length as a function of time are related to depolymerization processivity. We have also determined the parameter regime in which the rate of MT depolymerization is length dependent: length-dependent depolymerization occurs only when MTs are sufficiently short; this crossover is sensitive to the bulk motor concentration.

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L. E. Hough, Anne Schwabe, Matthew A. Glaser, J. Richard McIntosh, M. D. Betterton. 2008-12-19. Microtubule depolymerization by the kinesin-8 motor Kip3p: a mathematical model. https://doi.org/10.1016/j.bpj.2009.01.017

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