The Interplay of the N- and C-Terminal Domains of MCAK Control Microtubule Depolymerization Activity and Spindle Assembly
- 1 January 2007
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 18 (1), 282-294
- https://doi.org/10.1091/mbc.e06-08-0724
Abstract
Spindle assembly and accurate chromosome segregation require the proper regulation of microtubule dynamics. MCAK, a Kinesin-13, catalytically depolymerizes microtubules, regulates physiological microtubule dynamics, and is the major catastrophe factor in egg extracts. Purified GFP-tagged MCAK domain mutants were assayed to address how the different MCAK domains contribute to in vitro microtubule depolymerization activity and physiological spindle assembly activity in egg extracts. Our biochemical results demonstrate that both the neck and the C-terminal domain are necessary for robust in vitro microtubule depolymerization activity. In particular, the neck is essential for microtubule end binding, and the C-terminal domain is essential for tight microtubule binding in the presence of excess tubulin heterodimer. Our physiological results illustrate that the N-terminal domain is essential for regulating microtubule dynamics, stimulating spindle bipolarity, and kinetochore targeting; whereas the C-terminal domain is necessary for robust microtubule depolymerization activity, limiting spindle bipolarity, and enhancing kinetochore targeting. Unexpectedly, robust MCAK microtubule (MT) depolymerization activity is not needed for sperm-induced spindle assembly. However, high activity is necessary for proper physiological MT dynamics as assayed by Ran-induced aster assembly. We propose that MCAK activity is spatially controlled by an interplay between the N- and C-terminal domains during spindle assembly.Keywords
This publication has 85 references indexed in Scilit:
- Kinesin-13s form rings around microtubulesThe Journal of cell biology, 2006
- Review: regulation mechanisms of Kinesin-1Journal of Muscle Research and Cell Motility, 2006
- Efficient Mitosis in Human Cells Lacking Poleward Microtubule FluxCurrent Biology, 2005
- Roles of Polymerization Dynamics, Opposed Motors, and a Tensile Element in Governing the Length ofXenopusExtract Meiotic SpindlesMolecular Biology of the Cell, 2005
- Kinesin superfamily proteins and their various functions and dynamicsExperimental Cell Research, 2004
- Dynein/dynactin regulate metaphase spindle length by targeting depolymerizing activities to spindle polesThe Journal of cell biology, 2004
- The KinI kinesin Kif2a is required for bipolar spindle assembly through a functional relationship with MCAKThe Journal of cell biology, 2004
- Ran Induces Spindle Assembly by Reversing the Inhibitory Effect of Importin α on TPX2 ActivityCell, 2001
- Self-organization of microtubules into bipolar spindles around artificial chromosomes in Xenopus egg extractsNature, 1996
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970