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The interplay of the N- and C-terminal domains of MCAK control microtubule depolymerization activity and spindle assembly.
- Source :
-
Molecular biology of the cell [Mol Biol Cell] 2007 Jan; Vol. 18 (1), pp. 282-94. Date of Electronic Publication: 2006 Nov 08. - Publication Year :
- 2007
-
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.
- Subjects :
- Animals
Cell Extracts
Kinesins isolation & purification
Male
Microtubules chemistry
Mutant Proteins metabolism
Ovum cytology
Protein Structure, Tertiary
Proto-Oncogene Proteins c-mos metabolism
Spermatozoa
Xenopus laevis
Kinesins chemistry
Kinesins metabolism
Microtubules metabolism
Spindle Apparatus chemistry
Spindle Apparatus metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1059-1524
- Volume :
- 18
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Molecular biology of the cell
- Publication Type :
- Academic Journal
- Accession number :
- 17093055
- Full Text :
- https://doi.org/10.1091/mbc.e06-08-0724