Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality.
Aurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC), a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtub...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2014-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3912212?pdf=render |
| _version_ | 1818288619471765504 |
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| author | Michael Noujaim Susanne Bechstedt Michal Wieczorek Gary J Brouhard |
| author_facet | Michael Noujaim Susanne Bechstedt Michal Wieczorek Gary J Brouhard |
| author_sort | Michael Noujaim |
| collection | DOAJ |
| description | Aurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC), a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtubules are able to activate the CPC by contributing to Aurora-B auto-phosphorylation in trans. Aurora-B activation is thought to occur when the local concentration of Aurora-B is high, as occurs when Aurora-B is enriched at centromeres. It is not clear, however, whether distributed binding to large structures such as microtubules would increase the local concentration of Aurora-B. Here we show that microtubules accelerate the kinase activity of Aurora-B by a "reduction in dimensionality." We find that microtubules increase the kinase activity of Aurora-B toward microtubule-associated substrates while reducing the phosphorylation levels of substrates not associated to microtubules. Using the single molecule assay for microtubule-associated proteins, we show that a minimal CPC construct binds to microtubules and diffuses in a one-dimensional (1D) random walk. The binding of Aurora-B to microtubules is salt-dependent and requires the C-terminal tails of tubulin, indicating that the interaction is electrostatic. We show that the rate of Aurora-B auto-activation is faster with increasing concentrations of microtubules. Finally, we demonstrate that microtubules lose their ability to stimulate Aurora-B when their C-terminal tails are removed by proteolysis. We propose a model in which microtubules act as scaffolds for the enzymatic activity of Aurora-B. The scaffolding activity of microtubules enables rapid Aurora-B activation and efficient phosphorylation of microtubule-associated substrates. |
| first_indexed | 2024-12-13T01:59:16Z |
| format | Article |
| id | doaj.art-747602403a8c4c81a86a27dd0e2625b7 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-13T01:59:16Z |
| publishDate | 2014-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-747602403a8c4c81a86a27dd0e2625b72022-12-22T00:03:19ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0192e8678610.1371/journal.pone.0086786Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality.Michael NoujaimSusanne BechstedtMichal WieczorekGary J BrouhardAurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC), a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtubules are able to activate the CPC by contributing to Aurora-B auto-phosphorylation in trans. Aurora-B activation is thought to occur when the local concentration of Aurora-B is high, as occurs when Aurora-B is enriched at centromeres. It is not clear, however, whether distributed binding to large structures such as microtubules would increase the local concentration of Aurora-B. Here we show that microtubules accelerate the kinase activity of Aurora-B by a "reduction in dimensionality." We find that microtubules increase the kinase activity of Aurora-B toward microtubule-associated substrates while reducing the phosphorylation levels of substrates not associated to microtubules. Using the single molecule assay for microtubule-associated proteins, we show that a minimal CPC construct binds to microtubules and diffuses in a one-dimensional (1D) random walk. The binding of Aurora-B to microtubules is salt-dependent and requires the C-terminal tails of tubulin, indicating that the interaction is electrostatic. We show that the rate of Aurora-B auto-activation is faster with increasing concentrations of microtubules. Finally, we demonstrate that microtubules lose their ability to stimulate Aurora-B when their C-terminal tails are removed by proteolysis. We propose a model in which microtubules act as scaffolds for the enzymatic activity of Aurora-B. The scaffolding activity of microtubules enables rapid Aurora-B activation and efficient phosphorylation of microtubule-associated substrates.http://europepmc.org/articles/PMC3912212?pdf=render |
| spellingShingle | Michael Noujaim Susanne Bechstedt Michal Wieczorek Gary J Brouhard Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. PLoS ONE |
| title | Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. |
| title_full | Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. |
| title_fullStr | Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. |
| title_full_unstemmed | Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. |
| title_short | Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality. |
| title_sort | microtubules accelerate the kinase activity of aurora b by a reduction in dimensionality |
| url | http://europepmc.org/articles/PMC3912212?pdf=render |
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