The microtubule-based motor Kar3 and plus end–binding protein Bim1 provide structural support for the anaphase spindle
Open Access
- 7 January 2008
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 180 (1), 91-100
- https://doi.org/10.1083/jcb.200710164
Abstract
In budding yeast, the mitotic spindle is comprised of 32 kinetochore microtubules (kMTs) and approximately 8 interpolar MTs (ipMTs). Upon anaphase onset, kMTs shorten to the pole, whereas ipMTs increase in length. Overlapping MTs are responsible for the maintenance of spindle integrity during anaphase. To dissect the requirements for anaphase spindle stability, we introduced a conditionally functional dicentric chromosome into yeast. When centromeres from the same sister chromatid attach to opposite poles, anaphase spindle elongation is delayed and a DNA breakage-fusion-bridge cycle ensues that is dependent on DNA repair proteins. We find that cell survival after dicentric chromosome activation requires the MT-binding proteins Kar3p, Bim1p, and Ase1p. In their absence, anaphase spindles are prone to collapse and buckle in the presence of a dicentric chromosome. Our analysis reveals the importance of Bim1p in maintaining a stable ipMT overlap zone by promoting polymerization of ipMTs during anaphase, whereas Kar3p contributes to spindle stability by cross-linking spindle MTs.Keywords
This publication has 31 references indexed in Scilit:
- Vik1 Modulates Microtubule-Kar3 Interactions through a Motor Domain that Lacks an Active SiteCell, 2007
- Hypothesis testing via integrated computer modeling and digital fluorescence microscopyMethods, 2007
- Crosslinkers and Motors Organize Dynamic Microtubules to Form Stable Bipolar Arrays in Fission YeastCell, 2007
- Direct observation of microtubule dynamics at kinetochores in Xenopus extract spindlesThe Journal of cell biology, 2003
- Differential kinetochore protein requirements for establishment versus propagation of centromere activity in Saccharomyces cerevisiae The Journal of cell biology, 2003
- Differential Regulation of the Kar3p Kinesin-related Protein by Two Associated Proteins, Cik1p and Vik1pThe Journal of cell biology, 1999
- Dual-Axis Tomography: An Approach with Alignment Methods That Preserve ResolutionJournal of Structural Biology, 1997
- Computer Visualization of Three-Dimensional Image Data Using IMODJournal of Structural Biology, 1996
- Identification of essential components of the S. cerevisiae kinetochoreCell, 1993
- CIK1: a developmentally regulated spindle pole body-associated protein important for microtubule functions in Saccharomyces cerevisiae.Genes & Development, 1992