Mps1 Phosphorylation of Dam1 Couples Kinetochores to Microtubule Plus Ends at Metaphase
| Autor: | Sherry Niessen, Michelle M. Shimogawa, Trisha N. Davis, Cristian I. Ruse, John R. Yates, Susan E. Francis, Jeffrey N. Molk, Melissa K. Gardner, Erin White, Michael Ess, Kerry Bloom, David J. Odde, Beth Graczyk, Eric G D Muller |
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| Rok vydání: | 2006 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Cell division Cell Cycle Proteins Saccharomyces cerevisiae Spindle Apparatus CELLCYCLE Biology Protein Serine-Threonine Kinases Microtubules Models Biological General Biochemistry Genetics and Molecular Biology Spindle pole body Article Chromosome segregation 03 medical and health sciences 0302 clinical medicine Microtubule Chromosome Segregation Sister chromatids Phosphorylation Kinetochores Metaphase 030304 developmental biology 0303 health sciences Agricultural and Biological Sciences(all) Kinetochore Biochemistry Genetics and Molecular Biology(all) Protein-Tyrosine Kinases Cell biology Spindle apparatus Microscopy Fluorescence Mutation General Agricultural and Biological Sciences Tomography X-Ray Computed Microtubule-Associated Proteins 030217 neurology & neurosurgery Fluorescence Recovery After Photobleaching |
| Zdroj: | Current Biology. 16(15):1489-1501 |
| ISSN: | 0960-9822 |
| DOI: | 10.1016/j.cub.2006.06.063 |
| Popis: | Summary Background Duplicated chromosomes are equally segregated to daughter cells by a bipolar mitotic spindle during cell division. By metaphase, sister chromatids are coupled to microtubule (MT) plus ends from opposite poles of the bipolar spindle via kinetochores. Here we describe a phosphorylation event that promotes the coupling of kinetochores to microtubule plus ends. Results Dam1 is a kinetochore component that directly binds to microtubules. We identified DAM1-765, a dominant allele of DAM1 , in a genetic screen for mutations that increase stress on the spindle pole body (SPB) in Saccharomyces cerevisiae . DAM1-765 contains the single mutation S221F. We show that S221 is one of six Dam1 serines (S13, S49, S217, S218, S221, and S232) phosphorylated by Mps1 in vitro. In cells with single mutations S221F, S218A, or S221A, kinetochores in the metaphase spindle form tight clusters that are closer to the SPBs than in a wild-type cell. Five lines of experimental evidence, including localization of spindle components by fluorescence microscopy, measurement of microtubule dynamics by fluorescence redistribution after photobleaching, and reconstructions of three-dimensional structure by electron tomography, combined with computational modeling of microtubule behavior strongly indicate that, unlike wild-type kinetochores, Dam1-765 kinetochores do not colocalize with an equal number of plus ends. Despite the uncoupling of the kinetochores from the plus ends of MTs, the DAM1-765 cells are viable, complete the cell cycle with the same kinetics as wild-type cells, and biorient their chromosomes as efficiently as wild-type cells. Conclusions We conclude that phosphorylation of Dam1 residues S218 and S221 by Mps1 is required for efficient coupling of kinetochores to MT plus ends. We find that efficient plus-end coupling is not required for (1) maintenance of chromosome biorientation, (2) maintenance of tension between sister kinetochores, or (3) chromosome segregation. |
| Databáze: | OpenAIRE |
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