Direct measurement of the strength of microtubule attachment to yeast centrosomes
| Autor: | Kimberly K. Fong, Erik Yusko, Beth Graczyk, Trisha N. Davis, Michael Riffle, Aida Llauró, Charles L. Asbury, Krishna K. Sarangapani |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Saccharomyces cerevisiae Proteins Mitosis Saccharomyces cerevisiae Spindle Apparatus macromolecular substances Biology Microtubules Spindle pole body Chromosome segregation 03 medical and health sciences Laser trapping Calmodulin Microtubule Chromosome Segregation Kinetochores Molecular Biology Centrosome Kinetochore Cell Biology Yeast Biomechanical Phenomena Cell biology 030104 developmental biology Spindle Pole Bodies Brief Reports |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | Laser trapping is used to manipulate single attached microtubules in vitro. Direct mechanical measurement shows that attachment of microtubule minus ends to yeast spindle pole bodies is extraordinarily strong. Centrosomes, or spindle pole bodies (SPBs) in yeast, are vital mechanical hubs that maintain load-bearing attachments to microtubules during mitotic spindle assembly, spindle positioning, and chromosome segregation. However, the strength of microtubule-centrosome attachments is unknown, and the possibility that mechanical force might regulate centrosome function has scarcely been explored. To uncover how centrosomes sustain and regulate force, we purified SPBs from budding yeast and used laser trapping to manipulate single attached microtubules in vitro. Our experiments reveal that SPB–microtubule attachments are extraordinarily strong, rupturing at forces approximately fourfold higher than kinetochore attachments under identical loading conditions. Furthermore, removal of the calmodulin-binding site from the SPB component Spc110 weakens SPB–microtubule attachment in vitro and sensitizes cells to increased SPB stress in vivo. These observations show that calmodulin binding contributes to SPB mechanical integrity and suggest that its removal may cause pole delamination and mitotic failure when spindle forces are elevated. We propose that the very high strength of SPB–microtubule attachments may be important for spindle integrity in mitotic cells so that tensile forces generated at kinetochores do not cause microtubule detachment and delamination at SPBs. |
| Databáze: | OpenAIRE |
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